Russian car amplifier AAB-7900.1D - Page 1
Forum section: electronics / repair

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: March 10, 2023, 01:17:09 am
content: Customer cleaned the heatsink and off came all identification of model.Amp has two power supplies with all conections, seperate output is single channel.N ch enhanced TO-220 MOSFETs are marked H1 internal diode reads .470 andVgs is 3.14V that is pretty much all I can test for so far and do not know how to testfor RDS on nor have equipment to measure it.Owner found his manual so I have the model as added in subject.Deaf Bonce Apocalypse AAB7900.1D russian company, made in china sold all overthe world. 7900 watts RMS @ 1 ohm still stuck on a replacement MOSFET for thepower supply

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 10, 2023, 10:12:09 am
content: And... The MOSFETS in the DC-DC are blown? You would like toreplace them but don't know what to fit? Or nothing is wrong but you're just trying to identify the amplifier model?Sorry I don't see the point behind this topic.

author: Swake
author_rank: Frequent Contributor
timestamp: March 10, 2023, 02:49:07 pm
content: What can we help you with?Post some pics of that thing, we might be able to identify it.Is it OEM to the car, what brand is the car?Is it aftermarket?

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: March 11, 2023, 12:19:32 am
content: Aftermarket not OEM.Shorted MOSFETs that I can not identify.Cant do pictures till next week.Jeff

author: james_s
author_rank: Super Contributor
timestamp: March 11, 2023, 12:50:39 am
content: Mosfets in the DC-DC section? Your best bet if there are no non-shorted examples in the circuit is to either reverse engineer the circuit, or just look at what is used in a more common amplifier of similar power rating. Something like the IRF530 might work.

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: March 15, 2023, 12:48:32 am
content: It was 1 of 8 that shorted on one side of power section so Ihave 7 that work but very little experiance with MOSFETs asfar as design work goes with specs I can sub one IRF530 isolder part Vgs is in the area but voltage is high for this andcurrent is way low. I guess these at over 50A parts + some.I have IRF3205 and IRFB4227 its not these.Jeff

author: james_s
author_rank: Super Contributor
timestamp: March 16, 2023, 04:12:11 am
content: Personally I would replace all of them if I couldn't find a datasheet for the originals. Unless you want to pull one of the working original parts to analyze.

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: March 16, 2023, 02:23:45 pm
content: Certianly I will replace all of them but with what?How do I test for specs on an unknown MOSFET?The ones I have in stock are not good subs andthe highest current one I found in my 96 fet bookis 75A of coarse I do not have any to test.All I know how to test for I listed in the first post.Jeff

author: james_s
author_rank: Super Contributor
timestamp: March 16, 2023, 04:52:15 pm
content: Well you can guess. If you know the power output of the amplifier that gives you a good clue as to the power that the supply has to deliver. Failing that you can look at the rating of the input fuse and go off of that. It shouldn't really be that critical, these mosfets are likely two banks of parallel mosfets driving a push-pull transformer at a few tens of kHz. You'll want something rated for perhaps 100V at maybe 20-40 amps.