|
QUESTION NO. P090403-1: Sony
STR-DE925 Receiver. I replaced the power amps in one channel. The
new MN2488 (Q756)shows a closed circuit value of 4700 ohms across it's
emitter - collector. All of the other MN2488 (4) show open circuits
across the emitter - collector. This is the second MN2488 I received
with like this. Is this amp defective?
|
|
When checking the MN2488 junctions
you should isolate it from the board. I have found that the
MN 2488's can read different than another channel for a couple of
reasons . You should first check that the MP1620 complement does not
have an open junction. Also open 10, .47 ohm 1/8w resistors or
shorted or leaky biasing transistors.
|
|
QUESTION NO. P080403-4: Technics SE-CH404 Amplifier and sound processor Tuner Model ST-CH505 has
no sound from the speaker. After checking the components around
and using my signal tracer I found that the pre-amplifier was working
and there was signal on the input of the power IC. I changed the
power module SV1 3101D but no go.
|
|
If the input of SV1310D is good
and the output is missing or not there. If you can disconnect the
output from the unit then check for an output from the SV1310D .
Sometime you have to remove a unit from the circuit and then check it
out. If this is O.K., you have something in the rest of the
circuit loading it down. But at this point you know this part is
working O.K. You might find your answer somewhere down the rest of
the circuit.
|
| QUESTION NO. P61203-5: Sony STR-DE345 receiver has a broken volume pot, location RV-201. I need a part number for it. |
| Part number is 1-418-773-11 Encoder. |
|
QUESTION NO. P61303-4: Sony
STR-DE915 Receiver. I need the value of burned R540.
|
| 1K 1/4Watt, part number 1-249-417-11. |
| QUESTION NO. P50903-2: Kenwood KAC-823 amp. Replaced fried Q36 2SK1190 and repaired a few solder traces. When powered up, the FETs Q32 34 36 instantly get HOT but Q33 35 37 are ok. Where can I find a service manual for this amp? I tried all my resources. |
|
You can find a lot of service
stuff for Kenwood at www.pacparts.com.
This Pacific Coast Parts Distributers Inc's website. They have the
manual and other parts for this model number on their site. The manual
sells for $12.00 plus SH. Just go to their site and enter as guest
then type in your model number. Really good site.
|
| QUESTION NO. P51603-3: Pioneer vsx-4900s A/V receiver, need part numbers for d314,d315 on main board. |
| QUESTION NO. P50903-10: Pioneer DV-343 DVD player will accept disc and attempt to load menu but freezes on a black screen. Lens and rails are clean, laser is visible and all controls appear to function, but video output nonexistent. |
| Do you have the Pioneer Logo? I've had many Pi DVD's with bad RAM, IC14, new Pi part number K6T1008V2E-TB70. I've also replaced a ton of the transverse units (Optic Assy). |
| QUESTION NO. P41403-10: Marantz 2325 receiver intermittently after 5 to 10 minute warm up, relay goes into protection mode with loud pop coming from both speakers. Three seconds later relay turns back on. After this, speaker output remains uninterrupted as long as power is kept on. |
| VD 1221M diodes in the current source and mirror circuit of the power amp -H718 & H719 - I actually have the bulletin on this. New part was 1S1555, but I just series a couple of 1N914's. Best to do both channels. |
| QUESTION NO. P41503-5: Sony STR-D460Z receiver will power up fine then goes in to protect mode. |
|
Check all soldering throughout
unit specially the heatsink grounding screws and all other grounding
screws. Reset cpu by disconnecting unit from ac power source and
shorting out C110=0.22F,5.5v (located in front panel). Measure
audio o/p tri-amplifier output IC's NEN250(npn)(5 pin) and NEP250(pnp)(5
pin). Check dual emitter resistors (0.22 ohm,5w), nearby 180
ohm,2w resistors,47 UF,25v caps nearby, and 2SC4385 & 2SA1670.
Sony's website says to check IC150=HD6433258B55F=Sony #
8-759-275-31. Check bias & protection transistors for leakage
in either case if there is any leakage in either circuit, replace all of
the bias or protection transistors. Measure DC & AC waveforms
on each pin of IC701,IC651 & IC751=STK350-130A/230 (Sony old #
8-749-011-16 & New # 8-749-010-16)& compare with the two other
voltage amplifier IC's.
|
|
QUESTION NO. P41503-7:
Pioneer A/V receiver VSX-D498 shuts down when turned on, uses 3 output
amp (2pcs PAL007 & 1pc PAL008). Need source or replacement
for the output amp (PAL008).
|
| http://parts.pioneerelectronics.com |
| QUESTION NO. P42303-6: Pioneer cdx-fm1235s CD Changer/player. I need the part number of the two detector switches (Momentary N/O) on the top of CD transport. |
| http://parts.pioneerelectronics.com |
| QUESTION NO. P32703-5: Alpine 3566 carhifi-amp. I need replacement type for 2SC4024. |
| ECG & NTE part#2582. (Hi-speed switching regulator) |
| QUESTION NO. P40303-1: Sony CDX-4000R Car Stereo. I need the part number of a damaged rotary switch used for volume control. |
| To lookup part #'s go to http://the-hideout.net/techtalk/phpbb2/viewtopic.php?t=20. |
|
QUESTION NO. P10303-6: Coustic 360 amp will power up, but shortly after the peak LED comes on
and stays. No output to the speakers.
|
|
To answer my own question: Being
that the amp is quite old, the solder points had shaken loose with the
bass in the trunk. Resoldered about 10 points and amp has been
working great for about a month.
|
|
QUESTION NO. P:123002-1: Philips
FW750C CD player. The customer complains that when he put a cd and close
the door and after pressing play it displays searching and after a few
seconds it displays no cd. I cleaned the lens but it did not clear
the fault. The cd spins for a couple of seconds and stops. I
checked the spindle motor and the sledge motor outside the circuit with
a 9v dc supply and the motors run perfectly. Even though I changed the
spindle motor. While the cd is loaded the 5v supply is present and
drops to 0v after a couple of seconds. This player uses three
TDA7073A for it's loader control servo drivers and foc and rad. It
has a surface mounted microprocessor SAA7378GP. I want to check if
the TDA7073A which is a dual BTL power driver is working properly.
I have downloaded a complete datasheet file of the IC in the pdf
format at www.semiconductors.
philips .com/acrobat/2491.pdf. Is the entire laser pickup at fault
or the culprit is somewhere else?
|
| Replaced the new head. |
| QUESTION NO. P110802-9: Marantz 5050 vintage cassette deck, when powered up and press play without a cassette in, the motor is audible through the right channel meter. The meter pins successively against the stops. Is there a failed IC or opamp that could be causing this? |
| Clean the internal sliding record switch with a good contact cleaner. |
| QUESTION NO. P102102-2: Ford car radio blows fuses when turned on. I believe that one of the output transistors is shorted but I cannot cross reference the numbers on the output transistor to get a replacement. The radio is a Ford factory OEM radio from 1992 and looks like part number F1SF-19B165-BA. The transistors have TO 220 cases and one is definitely motorola.The part numbers are as follows; 5001FBAA ] [ Mot 70003FB, H8 40 QQLR8921, 274. |
| The parts are available from H+R AUTO RADIO 800-523-6605 www.hrautoradio.com which specializes in automotive radio repair. They are able to identify the parts by circuit board locator number and radio model number. |
| QUESTION NO. P100402-9: Sony STR-DE345 receiver has a cooked R736. I can't read value. |
| Sony STR-DE345, Sony new # 1-249-417-91, Sony old # 1-249-417-11, Description 1k ohm,1/4 Watt carbon resistor. |
| QUESTION NO. P92702-3: Profile car stereo amp. Power supply transistors-P50N06, I replaced with IRFZ44 and the amp came on, but with high current draw. I replaced two shorted outputs. Now the amp will come on and play with the gain down low. When the gain is increased, the power light will flash and the current draw increases and decreases in time with the power light. Do I need to change the Z44s back to P50N06s, or is there another problem? |
| Answering my own question, yes they will work. The problem at higher gain was caused by one of the output transistors breaking down on the other channel. |
| QUESTION NO. P83002-1: I am looking for a pair of complimentary output transistors for a Zenith Allegro audio system. The original transistors have the Texas Instruments logo on them and numbers NPN Transistor 1013 A7737 A-00 PNP Transistor 1012 A7737 A-00. |
| LG Electronics 1-800-243-0000 (Zenith & Goldstar). |
| QUESTION NO. P71602-9: Sansui AU-11000 amp. SV-02 by Sanken, the schematic says that it's a diode, Sanken's site says it is a varistor. My ECA (professional book of equivalent diodes, transistors etc..) says that it is a stabilizer diode of 1.2 v. An internet site says it is a diode that depends on temperature. What is it and what is a new equivalent component of it? |
| All those descriptions might apply. Sanken's SV-02YS (silicon varistor) is essentially two silicon diodes in series, giving a nominal forward voltage drop of about 1.2V at 1 mA. The exact voltage drop will vary with temperature, by roughly -4 mV per °C, as is typical for two silicon P-N junctions. Such devices are often used to compensate for changes in transistor characteristics, from variations in transistor Vbe diode voltage drops, with temperature. Possible substitutes might include ECG/NTE 605A, 1N4156, or Microsemi's MPD200, but it is best to use the original, if possible. |
| QUESTION NO. P61102-6: Technics SU-G95 audio equipment. I need the values for R703 and R704, +14V is dead, am I on the right track? |
| R703 and R704=Panasonic #'s ERDS1FJ100P, ERDS1FJ100, ERDS1FJ100, ERDS2TJ100, ERDS1FJ1R0. For more info on a parts list www.pasc.panasonic.com/epartr/. |
| QUESTION NO. P52202-8: Sony EXCD-21 AM/FM CAR CD player, I need the part number for IC 200 (Power Amp) chip. |
| IC 200 (Power Amp) chip=Sony # 8-759-426-49=Generic # HA13153A. |
| QUESTION NO. P60302-7: Sharp CD-C2900 audio equipment. As soon as the ac cord is plugged in the word (PROTECT) shows up. There is no function with the buttons are pressed. |
| If you are talking about a mini-stereo system, unsolder the STK output and see if it will power up. |
| QUESTION NO. P51502-1: Yamaha CA-44 household amp, the red tiny power light comes on and there is a slight low barely audible noise (no music or signal). When volume control is set at max during any input the left & right db output meter do not fluctuate. The only defective component that I found was an open resistor(10 ohm,270 ma,ceramic white) connected to the collector of transistor pcb location # 35=2SD476A=ECG196. Prior to replacing that resistor the relay would not click now it does allowing the power to reach the left & right channels but there is no voltage at the left & right output pins on the relay. I checked many components & soldering but no luck. |
| Answering my own question, another repair shop took a look at it before me and soldered a transistor (location35=2SD476A) in backwards & removed the plastic 5 mm X 5mm plates located inside the input selector switch and record selector switch so the switch contacts were not making continuity with the pcb board, I installed new plates, installed the transistor the proper way and the amp works good. |
| QUESTION NO. P50302-9: Optimus sta-3760 stereo receiver Cat no 31-3048. I need the values for R342, R344, R356, R360, R362, R364, and C318. |
| www.radioshack.com/ProdSupport/ProductSupport.asp then at the top right of the screen type in "31-3048" and the first of the 10 hits has a detailed parts list. |
| QUESTION NO. P40102-1: Need replacement potentiometers for Kicker car amplifier made by Piher. Two units, vertically mounted through circuit board, provide stereo gain adjustment. Joined through hexagonal detent with hex and knob. Each has three leads and white casing. Believe resistance to be from 100Kohms to 918Kohms. Also have capacitor from Rockwood brand American Eagle amplifier. CEW 50 v 4700uF 85degreesC two leads mounted vertically through circuit board. Used in amps power storage. Big around as a quarter and 1.5" long. Need replacement for this and mosfet switching device for same amp. Black with three leads on one end and metal screw down tab on other. Item# IRFZ44N. Other specifications are I (diode symbol)R752D 83, 53, and 2B. |
| Digikey (www.digikey.com) lists the Mosfet IRFZ44N. Digikey also has a wide selection of electrolytic capacitors, and your 4700 uF/50V, 85° should be available. You are probably looking for a radial cap, from the description, but check if it is polarized (positive and negative leads indicated), or nonpolarized. Choose a cap whose dimensions, and lead separations, will fit your board. Similarly, there are a wide variety of potentiometers available, from Digikey, and also Mouser (www.mouser.com), so check the dimensions/diagrams, to ensure they will fit. It sounds like a 1 Meg-ohm potentiometer. |
| QUESTION NO. P41502-5: Sony portable radio (boom box) CFS-W350. I need the Sony part #'s & PRB part #'s for the two different sizes of tapedeck belts. |
| Answering my own question, I found out that PRB #'s SCY5.5 & SCY6.5 worked perfectly. I cannot figure out why PRB does not list this model in their book or website. |
| QUESTION NO. P326-4: Sharp CD-C622 mini component system as soon as it is plugged in goes into "Protect Mode". (The owner of unit connected to many speakers.) Checked RY801, C815, and Q803 all are okay. |
| Replace audio output IC and check nearby low ohms resistors for open. |
| QUESTION NO. P40802-10: Sony compact disc deck receiver HCD-D170 when plugged in there is no display or power. I think it went into protection mode. I can hear a relay click. I check the fuse it is fine. |
| In main board the microprocessor, IC601 needs replacing. Sony old # 8-759-248-06,new Sony 8-759-325-41. |
| QUESTION NO. P320-6: JVC CA-c33BK mini stereo will not eject cd magazine or open single disc drawer. I can eject magazine by lifting internal lever. The cd motor is not receiving any voltage but all other functions of the stereo are working fine. Cassette decks, tuner, etc. Cd functions light in display but ot will not load eject etc. |
| First of all, check out CD mechanism power supply R801 +10V, R802 -10V, Collector of Q801 +5V, Pin 6 of JB751 +12V, Pin 7 of JB751 -12V. |
| QUESTION NO. P40902-10: JVC RX-318 Receiver needs a new volume control rotary switch. It is made by ALPS and it has a number on it of QVDB71B-E15B15S- 746M. Where can I find one of these or a sub? |
| www.jvcservice.com |
| QUESTION NO. P326-9: AMC 25100 amplifier. I need subs for A1386 & C3519 both by SK. |
| Possible substitutes for the Sanken pair, 2SA1386 and 2SC3519, with similar or higher ratings, include the pairs 2SA1386A/2SC3519A, 2SA1302/2SC3281, 2SB1529/2SD2328, 2SA1294/2SC3263, 2SA1962/2SC5242, 2SA1986/2SC5358, and MJL1302A/MJL3281A. |
| QUESTION NO. P322-8: Denon DRA-335R audio receiver. Need a sub or replacement for transistors labeled SKC3853 and SKA1489. |
| The "SK" stands for SanKen, who manufactured 2SC3853 and 2SA1489. For replacing the pair 2SC3853 and 2SA1489, SanKen itself recommends their own devices, 2SC4466 and 2SA1693. Other possible replacement pairs are 2SD895/2SB775, and 2SD1110/2SB849. One potential source, for both the originals and subs, is MCM Electronics (www.mcmelectronics.com). |
| QUESTION NO. P31-6: Sony STR-AV1070 audio had intermittent large crackling noise. Located unstable solder joints near R975 with traces of overheat. Color code is not legible. |
| Replace Q971=Sony # 8-729-140-96=Generic # K32/2SD774, Replace R975=Sony # 1-249-409-11=Generic # 220 OHM,1/4 W with new #, Sony # 1-212-990-0=Generic # 220 OHM,1/2 W. |
| QUESTION NO. P221-9: Akai AM-A90 Amplifier , output mosfet transistors damaged, numbers 2SJ115 and 2SK405; these transistors are discontinued, what subs can I use? |
| To replace the Mosfet pair 2SJ115 and 2SK405, the closest pair is 2SJ200 and 2SK1529. Less close, but might substitute, are the pairs 2SJ201/2SK1530, or 2SJ440/2SK2467. Possible US sources for 2SJ200 or 2SK1529 include Nationwide (www.neiparts.com) or Audio Lab of Georgia (www.datadart.com), among others. If in Europe, try Borbely Audio (www.borbelyaudio.com). |
| QUESTION NO. P213-10: Technics SA-310 receiver was not getting any power. I replaced the fuse (found under the cover) and powered up and the fuse immediately blew. I cannot see any visual damage to the power supply or other components. |
| If the bridge rectifier is ok in the power supply, then the problem is most likely audio output section. |
| QUESTION NO. P21-7: Sony EXCD-21. I need data sheets or cross reference for transistor D2394, 2SD2394 or BD937F. |
| 2SD2394 and BD937F are 3 Amp, audio-frequency transistors, in TO220F cases. Rohm's 2SD2394 is rated 80 Vcbo, 60 Vceo, 3 Amp, 25 Watts, and a datasheet is available at www.nedis.com/datasheets/datasemi/2SD/2SD2394.pdf In the TO220F (insulated) style, two possible crosses are 2SD1266A (preferred), or 2SC3851; Mouser Electronics (www.mouser.com), among others, lists these. Or, if an insulating washer is added, you could try a plain TO220 type, like an NTE152, or a BD241B (also listed by Mouser). |
| QUESTION NO. P21-5: Profile baja 640 car amp. The outputs were blown, one on each side tip 107 and tip102. I ordered these chips but when they blew, they took out the mosfet power transistors. They are 36n06v, I need a sub or source. |
| MTP36N06V is a 60 Volt, 32 Amp, Rds[on] <0.04 ohm, 90 Watt, N-channel Mosfet, TO220 style. It can be subbed by STP36NE06, IRFZ44E, or NTE 2389 (www.nteinc.com). Mouser Electronics (www.mouser.com) lists STP36NE06; and Digikey Corp. (www.digikey.com) lists IRFZ44E, among others. |
| QUESTION NO. P12-6: Sony STR-GX900ES receiver originally front left channel (A & B) had very low audio o/p but now all channels (front, back & center) have no output and sometimes turned on the word "PROTECTOR" flashes on the display. This model does not use the common failure output transistors MN2488-OPY-M (2SD2488) & MP1620-ODY-M (2SB1620). I checked the dual emitter resistors (0.22 ohm,2W) and nearby 100 ohm resistors as well as most components and tightened grounding screws (checked soldering) but still no audio o/p. |
| Check the bias and protection transistors for leakage. In either case if there is any leakage in either circuit, replace all of the bias or protection transistors. |
| QUESTION NO. P1227-1: Sony STR -D560Z audio equipment blew out transistors MN2488 & MP1620. I replaced them, dual emitter resistor (.22ohm *2) and an 180 ohm resistor. It is still in "protection mode", how can I reset or clear it? |
| Check the protection transistor for leakage. If any are leaking, replace them all. |
| QUESTION NO. P122-7: Jensen Car Audio Amp model KA4040HLx will not turn on. I replaced the PWM chip and all 8 mosfet switches and still nothing. I suspect QS1 a transistor (to-92) that is marked P4M this crossed to an ECG 121 but the ecg 121 is a TO-3 case so obviously will not work. |
| A P4M, in the TO-92 case style, will be a 400 Volt-rated SCR, from NEC; its full number is 03P4M. B&D Enterprises (www.bdent.com) is listing 03P4M, on-line. Mouser Electronics (www.mouser.com), among others, lists EC103D (Teccor) and P0102DA (ST Micro), which might also substitute for this SCR. |
| QUESTION NO. P17-4: Kenwood KA-5500 amplifier, all 4 output transistors are blown. The number on them is (2S)D388A and (2S)B541A (both are NEC). I need the equivalent of these even if it means changing the Emitter Collector Base layout. I also like to know if these are PNP or NPN and if they are bipolar then which one of them is PNP and NPN. I also need the equivalent to a A733 transistor from the preamp. |
| The 2SD388A is an NPN type (110V, 8A, 80W). Types to compare for sub are 2B3442, 2SD551, 2SD732, MJ15001. The 2SB541A is the PNP complement. Types to compare here are 2SA981, 2SA982, 2SA1141, 2SB681. The A733 is PNP, 60V ,0.1A ,0.25W. Types to compare are BC 212, BC 257, BC 307, BC 557. |
| QUESTION NO. P1220-4: Technics SUG91 works fine until volume is turned up to -24db, then goes into protect. Replaced Output IC, still have problem. Schematic shows protect circuit to be in output IC. |
| Make sure cooling fan operates as volume is turned up. If it doesn't, check for defective driver circuit or open/binding motor. If motor operates, problem is most likely on the Crossover networks inside the speaker towers. High volume heats the solder connections--usually for the capacitors--and causes an open circuit. I've seen many capacitors destroyed by the heat generated from too much current to the speaker Crossover by high volume. If bad solder connections are found, replace the affected capacitors. If other connections look suspicious, desolder and resolder them. |
| QUESTION NO. P1129-5: Technics CD player SL-P720 has been realigned and cleaned, but some CDs will simply not initialize, and yet some play perfect. Occasionally, a CD will start fine, but will get confused if asked to skip tracks, but will play fine from beginning to end sequentially. The o-ring at the end of the sled was replaced with no change in results. |
| A failing laser causes the symptoms you described. Well made cd's are much easier to read and will often play in those systems. You may find that it works better after running for some time. You can try to increase the output of the laser by adjusting the potentiometer on the laser' board or on the main board itself. Do not over-adjust or you will burn out the laser. I have never heard of anyone replacing the laser itself. |
| QUESTION NO. P1129-6: Technics CD player SLPG440 will clear the display and reboot, like it has been turned off and on again. Track 1 will play. It happens randomly and nothing seems to be evident that would cause it. |
| Try to adjust the pot (variable resister) under the lens. Most of the time it works. |
| QUESTION NO. P1121-4: Sony cdx-4090 fm/am compact disc player works fine but the display. Does not have a back light bulb. What illuminates the led display? Display is present but not illuminated. |
| Measure DC voltage at cd lamp and if 6v,9v, or 12v is present then replace mini bulb commonly called "wheat of grain bulb". |
| QUESTION NO. P1025-1: Sony str-de915- audio equipment enters protect mode when turned on. I found that the front channel transistors were bad. I was told I could use ECG2355 and ECG2356 to replace the MN2488 and MP1620. Is this true? |
| ECG2355 and ECG2356 are tiny digital-switch transistors, rated for 0.1 Amp maximum. |
| QUESTION NO. P814-9: Sony STR-DE705 Receiver enters "protected mode". Has the same parts as some of the others "mp1620 and "mn2488". Is there an easy check for the outputs to see which one is bad? |
| Checked same transistors on similar Sony receiver by checking resistance between the center pin and the side pins. The Bad Output transistors should have no resistance between the right pin and the center. At least that was the way I found them. If they are bad you will probably need to replace the dual emitter resistor, probably 2watt .22 ohm and some 180 ohm resistors nearby. At least check them and look for burnt components. |
| QUESTION NO. P814-5: Orion Cobalt 260 car audio amp. I need a source for part numbers smw20p10 and smw45n10. I believe these are old Siliconix part numbers, but I am not certain. Direct or upgrade replacement parts would be fine. |
| SMW20P10 (P-channel) and SMW45N10 (N-channel) are 100 Volt Mosfets, in TO-247AD cases. You might substitute IRF's IRFP9140 for SMW20P10, and IRFP150N or ST Micro's STW50N10, for SMW45N10. Digikey (www.digikey.com) carries the IRF lineup, and Mouser (www.mouser.com) carries ST Micro FET's. These substitutes use the TO-247AC style case, which has slightly shorter leads than TO-247AD, if that matters. |
| QUESTION NO. P731-8: JVC RX-709VT amplifier. I need the value of IC702. |
| IC702 is a "SuperA 23H4" I'm not sure where you can get a replacement. |
| QUESTION NO. P730-1: Pioneer PDM701 CD player cycles through all the disks spinning them for about 10 seconds. The laser pickup moves out and the disk speeds up a little before it stops and goes to the next disk. Changed the optical pickup with NEW unit -no change. Can the spindle motor need replacing even though it spins? There is no disk info readout on display. |
| Have replaced many Pioneer spindle motors, will not spin up fast enough. Sometimes a little shot of Blue Shower in the motor will make it work. |
| QUESTION NO. P720-7: I need a cross reference # for a diode out of a pioneer CD player circuit board. The p/n from Pioneer is S5688G, but they want $8.00 for shipping. |
| Toshiba makes a General Purpose rectifier that is called S5688G, rated 400 Volts, 1 Amps. It is a short rectifier, marked with a "T" (for Toshiba), and a marking code "G", followed by a date number. Or check the diagram in the datasheet, to confirm if this is your diode, at doc.semicon.toshiba.co.jp/pdf_e/docweb123/e002787.pdf. If this is the correct device, then electrically it is equivalent to 1N4004 (except a stubbier case). You can get 1N4004 (or sub any higher number, up thru 1N4007) widely; e.g., Radio Shack. |
| QUESTION NO. P723-10: Sony Receiver would shut down in "protect" mode. The R channel output transistors are shorted between the collector, and emitter. Where can I find transistors MN2488, MP1620? Are there any generic replacements? I cannot find these on MCM Electronics. |
| Audio Lab of Georgia (www.datadart.com) and Nationwide (www.neiparts.com) list MN2488 and MP1620, online. The generic versions 2SD2488 and 2SB1620 may cost less, so compare their pricing, from these two suppliers, as well as from MCM. |
| QUESTION NO. P719-9: Fostex XR-7 Multitrack Tape Recorder that has no tape motion, solenoids fire. The motor appears to be fine. I have isolated the problem down to the driver transistors whose part numbers are B123ESJ, C144ESH, and A144ESH, I cannot find exact crosses for these parts and I'm wondering if SK9959 (B123ES), ECG2359 (C144ES), and ECG2360 (A144ES) are compatible being that they're missing the last letter in the cross. |
| Those substitutes should be fine. These are all digital transistors, from Rohm, with built-in biasing resistors. The first letter in the suffix defines the resistor configuration, so it is critical to match that. The second letter is the package type, with 'S' indicating a thru-hole SPT type, not an SMD package. It should not matter if an SPT, or a TO-92 package, is used by the substitute. |
| QUESTION NO. P717-2: Sony STR-DE425 Receiver blows a 3 Amp 125 Volt fuse. Replaced output transistors mn2488 and mp1620 and the dual emitter resistor that were all bad. The fuse is still blowing. If I pull the output transistors, all of them, off the heat sink then it powers up briefly until it goes into "protection" mode. |
| To run tests, take the door off the bottom of the receiver. There is a ribbon cable that connects the front panel to the main amp board, usually labeled. One lead at the end is labeled "protect". Slice the foil line going to it, that will take it out of protect mode to run tests. |
| QUESTION NO. P75-4: Technics SU-V8 Amplifiers which "crackles" on the right channel when the volume is turned past 2. The fault does not have anything to with the pre-amp but lies somewhere in the output stage. I cannot find any faulty components. If left on for too long at high volume, the amplifier goes into protection. I was going to change the output transistors but they do not seem to be available anymore. |
| Other than just the volume control needing cleaned, I would suspect the volume control IC, if this model uses one (probably does if it has the volume control that will spin infinitely in either direction). I believe it is a TC9212. |
| One thing that gets overlooked in such cases are the capacitors in the final output. As reliable as these passive components can be, they should be checked for shorting, which causes the crackling when the potential is just under what would be required for a steady arc. Once that potential is exceeded, such as when volume is turned up beyond a certain point, that area that had the intermittent arcs now becomes a dead short. Replacements are cheap enough, and if the obvious volume control cleaning does not resolve the issue, or the replacement of the volume control leaves no change in performance, or in the event the amp used the volume control chip, and that was changed with no results; change the electrolytics in the output stage. |
| QUESTION NO. P525-1: Sony TA 4650 Audio amplifier, the out put transistors have failed. I need a source or sub for the V fets 2 SK60 and 2SJ 18. |
| Nationwide (www.neiparts.com) is listing 2SK60 and 2SJ18, online. |
| QUESTION NO. P922-8: I want to know if I can get a part for a cd car stereo. It is a transistor, the transistor is a (Sony,279-87 4k2) the model number for the car is a Sony, CDX-4090. What I need to know is if I can buy that part. |
| Your Sony transistor can be attained by calling Andrews Electronics at 800-289-0300. If you still have a problem, email me at elecplus@gte.net and I'll get you the information you need, like a direct sony part number. |
| QUESTION NO. P524-2: I need replacement type for D1717 and B1162 (mosfet?), as found in the output-section of a Kenwood KA-7020 hifi-stereo-amp. |
| For 2SD1717, try Nationwide (www.neiparts.com). For 2SB1162, try Audio Lab of Georgia (www.audiolabga.com) or MCM Electronics (www.i-mcm.com). These are bipolar, NPN and PNP transistors, not MOSFET types. |
| QUESTION NO. P518-8: Sony amplifier XM-640 has a shorted transistors c3345 and a1328 located right to the input of the amp. I need their values. |
| 2SC3345 and 2SA1328 are complementary NPN/PNP transistors, in TO-220 cases. Their specification values are Vcbo = 60V, Vceo = 50V, 12 Amp, 40 Watt, gain = 70-240. The 2SC3345 (NPN) is 0.2 usec T-on, 0.2 usec T-fall, 1 usec T-stg; Cob = 180 pF, Ft = 90 MHz. The 2SA1328 (PNP) is 0.3 usec T-on, 0.5 usec T-fall, 1 usec T-stg, Cob = 320 pF, Ft = 70 MHz. Nationwide (www.neiparts.com) or Dalbani (www.dalbani.com) are potential sources. |
| QUESTION NO. P517-5: Sony tan-15F power amplifier, the one channel's output transistors are missing, but the other has a C2681 and a A1141 (both NEC). What transistors can be installed? |
| The full numbers are 2SC2681 and 2SA1141. If your supplier cannot provide these, then ECG/NTE 36 and 37 should be able to be substituted. |
| QUESTION NO. P427-8: Technics SA-EX300 audio equipment intermittently overload detection kicks in even without speakers. Thought it was an overheating problem or possible cold solder joint but tried Cold Air and still had same problem. |
| The cooling fan should be a PCB mount. Check the solder at the cooling fan. |
| QUESTION NO. P410-5: Marantz PM 54DS amp. I need a source or sub for SKT 3062IV. Can I replace it with SKT 3062 or SKT 3062II? Where can I find data sheet of SKT 3062 IV? |
| You can find it at MCM Electronics for $10.23 www.mcmelectronics.com. You can get the datasheet at www.freetradezone.com sign up is free. |
| QUESTION NO. P412-4: Pioneer RX-Z16 amp/cassette player will not power up. All voltages seem to be correct, has a strange switch unit. |
| Found problem to be surround sound switch shorted permanently. Removal or replacement of the switch allowed the unit to switched on. |
| QUESTION NO. P328-2: Technics sl-pj22-kek CD player spins disk but will not read disk and continues spinning until switched off. Tried cleaning laser lens, still the same. |
| Replace the eyeball & align following Matshushita's procedure in any service manual for the slpj series or slp100 thru slp500. |
| QUESTION NO. P412-10: Trace Elliot Super tramp guitar amp. I need a sub for a small signal transistor, seems to be a national semiconductor, part number j112 (it has a "518" too). |
| National's J112 is a JFET switching transistor; it is N-type (not P-type, like the 2SJxxx devices). J112 has also been made by Fairchild, Siliconix, Temic, among others. A convenient source would be RadioShack Online (www.radioshack.com; 1-800-THE-SHACK) which lists the J112 itself, as cat.# 900-5487. |
| QUESTION NO. P45-3: Trace Elliot Super tramp guitar amp. The power output transistors (part number j162 and k1058) are dead. I cannot find the replacements. I need the part number to replace these. |
| Their full numbers are 2SJ162 and 2SK1058, and they are a matched pair of P and N channel Hitachi Mosfets, 160V, 7 Amp, 100W. Both parts are actually quite widely available, for roughly $10 apiece, from places like NEI (www.neiparts.com), Dalbani (www.dalbani.com), MCM (www.mcmelectronics.com), Audio Lab of Georgia (www.audiolabga.com), and B&D (www.bdent.com) For a fair bit more, NEI does list a genuine matched-set of these two. |
| QUESTION NO. P316-5: Fisher ph-d800 cd/boombox, during adjustment of tgain, cd was playing and suddenly went dead, no led display, nothing. DC-DC converter ok [+5.6v,-5.6v,13.6v in]. Also note tgain pot wiper is at ground. The micro [Lc7860j] crystal osc is not working. Cannot find pinout for b+ point on ic and all voltages around ic low. |
| I found the problem to be Q705 [1012/g/9c=ecg85] located next to dc-dc converter box. Display works normal now and cd unit works again. |
| QUESTION NO. P38-7: JVC rx-778vbk had plugged in surround speaker wires into 120 vac line which was connected to amp. The 6.3amp fuse blows and no display. Nothing tests shorted. Is the micro in display panel bad? The power transformer is ok. |
| Replaced q1851 [2sd2390], q1853 [2sb1560], f1 [6.3 amp f type]. The transistors were shorted (Darlington complimentary pairs). |
| QUESTION NO. P38-6: Sony STR-D511 Receiver. Unit hooked up to a 4 ohm speaker which placed the unit into protect mode multiple times. Eventually the unit was fried and will not power on from over heating. |
| Turn the speakers off if the unit is operational enough to power up and see if it trips without a loaded output. If it does, check for any visibly damaged components in the biasing networks of the output and driver stages of the outputs. If no suspects are found, check the insulating strip of Mica behind the Collector or Drain of the output transistors. Find out which supply lines go to different sections, disconnect them and connect them back one by one. When it acts up you will know what circuit block the problem is in. This would at least narrow your search. |
| QUESTION NO. P215-10: I have two Yamaha REV 5 reverbs that both have difficulty booting up. I replaced several components on the PS (IC1, PC1&2, Q1). Cannot cross reference Q2- 2SC2655 or D1- S1WB40. Output voltages are low by about 1 vdc and there is much ripple. Caps test all OK with ESR meter and diodes all seem OK as well. |
| Try changing memory battery. You must do it that way to connect some third battery on board till you replace old with now one. |
