Thank you perry for all the help. while I'm waiting for the parts i will try to temp a harder amp. Its a fosgate 800a2 that i bought and did not work. The first time i put power to the amp it turn on for about one min. And dead. I open it up and see that c20 r15 c19 is missing. I then check power without the remote and 14v. With the remote to power 10v. I have a drain some where. I check the Fet power and the seem fine. I check the outputs 5 IRF9640 and 5 IRF640 found that are usual reading.
Resistance from leg 1-2
Q211: 62 ohm
Q212: 164 ohm
Q213: 164 ohm
Q214: 164 ohm
Q215: 164 ohm
Q216: 79 ohm
Q217: 79 ohm
Q218: 79 ohm
Q219: 2.4 ohm
Q220: 9.1 ohm
Resistance from leg 2-3
Q211: .4 ohm
Q212: .6 ohm
Q213: .6 ohm
Q214: .6 ohm
Q215: .6 ohm
Q216: 60 ohm
Q217: 60 ohm
Q218: 60 ohm
Q219: .6 ohm
Q220: 1.3 ohm
After I measure those i found two transistor looks like its been change. found a Lm317T WKO049849 malaysia next the 10th IRF640. Across the other side same place a LM317T W99019735 china ST. I don't think these are stock parts.
Resistance from leg 1-2
Q211: 4.5 ohm
Q212: 3100 ohm
Resistance from leg 2-3
Q211: 5.5
Q212: 120 ohm
I wil measure the gates resistor and post later.
Resistance from leg 1-2
Q211: 62 ohm
Q212: 164 ohm
Q213: 164 ohm
Q214: 164 ohm
Q215: 164 ohm
Q216: 79 ohm
Q217: 79 ohm
Q218: 79 ohm
Q219: 2.4 ohm
Q220: 9.1 ohm
Resistance from leg 2-3
Q211: .4 ohm
Q212: .6 ohm
Q213: .6 ohm
Q214: .6 ohm
Q215: .6 ohm
Q216: 60 ohm
Q217: 60 ohm
Q218: 60 ohm
Q219: .6 ohm
Q220: 1.3 ohm
After I measure those i found two transistor looks like its been change. found a Lm317T WKO049849 malaysia next the 10th IRF640. Across the other side same place a LM317T W99019735 china ST. I don't think these are stock parts.
Resistance from leg 1-2
Q211: 4.5 ohm
Q212: 3100 ohm
Resistance from leg 2-3
Q211: 5.5
Q212: 120 ohm
I wil measure the gates resistor and post later.
Q211, 219 and 220 appear defective. The emitter resistors for Q219 and 220 appear to be open also. Cut the legs free on the defective ones and then you can recheck the outputs to determine if they're defective. They all have to be changed but having them out of the circuit will allow further testing.
After removing the shorted outputs from the circuit, then you can reliably check the gate resistors. They generally fail open.
I'm not sure why you're reading something less than 10 ohms. U3 and U4 are supposed to be the LM317 and LM337. You should read ~the same as the resistor connected between the legs (nothing less than ~120 ohms.
Mouser:
511-LM317T
512-LM337T
With these amps, you can typically expect at least 20-30 parts to fail or to have to be replaced.
Have you ever replaced parts on the MEHSA insulators?
After removing the shorted outputs from the circuit, then you can reliably check the gate resistors. They generally fail open.
I'm not sure why you're reading something less than 10 ohms. U3 and U4 are supposed to be the LM317 and LM337. You should read ~the same as the resistor connected between the legs (nothing less than ~120 ohms.
Mouser:
511-LM317T
512-LM337T
With these amps, you can typically expect at least 20-30 parts to fail or to have to be replaced.
Have you ever replaced parts on the MEHSA insulators?
I have not, but i will try. I will buy one of the Mini Butane Iron Gun
and try my best. I think i will replace 5 of the IRF9640 and 5 of the IRF640. I had a friend open up his amp to compare and he had 337t and 317t on the two that are replace with china and may parts. Are this the original? Before i oreder anything i will cut the legs and retest them 1st.
and try my best. I think i will replace 5 of the IRF9640 and 5 of the IRF640. I had a friend open up his amp to compare and he had 337t and 317t on the two that are replace with china and may parts. Are this the original? Before i oreder anything i will cut the legs and retest them 1st.
You can try it. On many amps, you can cut out the bad components and they will power up. Generally, these do significantly more damage and will not produce audio from the blown channel.
The following graphic shows a typical repair and the parts that fail (or have to be replaced) when the outputs fail.
http://www.bcae1.com/temp/punch800a2repaired.swf
The following graphic shows a typical repair and the parts that fail (or have to be replaced) when the outputs fail.
http://www.bcae1.com/temp/punch800a2repaired.swf
okay, I cut the legs of
q311:
q312:
q314:
q315
q316:
q317:
Left the legs on
q318
q319
q320
and now power up. measure
r340: 83 ohm
r342: 118.6 ohm
r344: .4
r346: .4
r362: .4
r366: .4
r368: .4
r370: .4
r372: .4
r374: .4
Found 2 resistor are bad. So are 5 IRF9640 and 3 IRF640. What other parts do you think i should check?
q311:
q312:
q314:
q315
q316:
q317:
Left the legs on
q318
q319
q320
and now power up. measure
r340: 83 ohm
r342: 118.6 ohm
r344: .4
r346: .4
r362: .4
r366: .4
r368: .4
r370: .4
r372: .4
r374: .4
Found 2 resistor are bad. So are 5 IRF9640 and 3 IRF640. What other parts do you think i should check?
With a high power lighted magnifying glass, you can look for a bubble or other defect in the center of the top surface of the SMD resistors (see attached). Also look for signs that the solder overheated on them. Those will likely be defective.
You will also need to replace the MPSA06 and MPSA56 driver transistors. Even if they check OK, replace them. If they're leaking and you power up the amp with the new components, they will cause the outputs to fail again.
You will also need to replace the MPSA06 and MPSA56 driver transistors. Even if they check OK, replace them. If they're leaking and you power up the amp with the new components, they will cause the outputs to fail again.
Attachments
r334:20 ohm
r335:10 ohm
legs 1 to 2
q324:3.2ohm
q325:3.5ohm
legs 2 to 3
q324:2.5 ohm
q325:3.5ohm
r328:994 ohm
r355: 991 ohm
legs 1 to 2
q329: 4.8 ohm
q330:180.5 ohm
legs 2 to 3
q329: 998 ohm
q330:3.5
r362: 20 ohm
r363: 20 ohm
r378: 51 ohm
r364: 10.1 ohm
r366: .4 ohm
r368: .4 ohm
r370: .4 ohm
r372: .4 ohm
r374: .4 ohm
looks like the r364 is bad also?
r335:10 ohm
legs 1 to 2
q324:3.2ohm
q325:3.5ohm
legs 2 to 3
q324:2.5 ohm
q325:3.5ohm
r328:994 ohm
r355: 991 ohm
legs 1 to 2
q329: 4.8 ohm
q330:180.5 ohm
legs 2 to 3
q329: 998 ohm
q330:3.5
r362: 20 ohm
r363: 20 ohm
r378: 51 ohm
r364: 10.1 ohm
r366: .4 ohm
r368: .4 ohm
r370: .4 ohm
r372: .4 ohm
r374: .4 ohm
looks like the r364 is bad also?
Q329/30/24/25 are the MPSA06/56. Pull them out of the circuit and recheck the resistors near them.
Also pull the 0.1 ohm resistors. That will allow you to more accurately read the value of the resistors like R364.
Thanks for taking the time to post the results in a way that's easy to read.
Also pull the 0.1 ohm resistors. That will allow you to more accurately read the value of the resistors like R364.
Thanks for taking the time to post the results in a way that's easy to read.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- General Interest
- Car Audio
- Rockford fosgate 800a2