Recent content by nabeelsayegh

Bump... Please...I am desperate here. Anyone have one of these that could help me out? At this point, I'd be willing to buy a fully working m4000a if it means I can have a reference unit to fix the one I got here.

Great thread on this topic. I am actually having the same problem. full system recap (except for main filters), replacement of small signal transistors with KSA992/KSC1845. pots and switched scrubbed very well. I replaced C903 (the 3.3uf/50V mylar cap) with a Panasonic polyester equivalent...

Unfortunately, I never got one. I had to settle for some 'educated' guesses.

Wanted to circle back on this to see if anyone has an M4000a amplifier that would be willing to help me out with getting some reference photos from your unit. I am willing to compensate you for your time. I need to get this repair done asap and due to the absolute lack of information available...

So, I just saw something that caught me off guard. On the schematic for this amplifier board, there is a notation in two spots that say "open for LH1000". Based on where these are at, I just realized that these are jumpers on the circuit board. Well, If these are supposed to be open for an...

Interesting. So i ended up lifting the two diodes you mentioned to see what would happen and before i could test the result, the bias pot started to smoke. I'm going to have to put them back in place and re-test this again. I appears i had some excessive current going through that pot to get...

I had pulled all 8 of the output transistors and checked them independently and they are all testing good. Did a diode test on them and clamped them into a transistor tester. gains all seemed to match. Same was true for the driver pair. Do you think that the two transistors i replaced (to...

Voltage across R314 i am measuring about 1.6V. Q308's BE voltage is 0.6V. Re-measured the EC voltage and it is about 2.2V.

Sorry, was out of town for a while and just got back to the shop. Going to take another look at this now and see what I can find.

No takers?

One other thing of note....Transistor pairs Q306/307 and Q304/305 seem to be getting pretty hot. Not sure if this is 'normal' or not, but mentioning it nonetheless.

Hoping someone can help me out with this amp. This came in due to what appears to be a common problem with the differential 2SC3200 transistors causing high DC voltage at the outputs which in turn puts the amp intermittently in protection mode. Based on my research, I had installed a pair of...

I pulled this unit back onto the bench after tabling it for almost a year. I am still having the same issues and could really use some help. At the very least, can someone confirm that it is not "normal" for this desk to only running for a few seconds in FF/RW. I assume no...but i feel like i...

Hello. I am working on a DAS Action 15A power amplifier and apparently it has these amp modules (3 of them) that plug into a main board. One module powers the Compression horn and the other two run in parallel and power the woofer. I have identified one bad module and it has a pair of these...

Absolutely! You are an absolute life saver. I am actually going to be out of town this coming week so this will be good timing. The nice thing about this unit is that it is modular.....except for the front panel...which is where i think i am going to need some photos of. I may also need to...