Bass Audio BA2150

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Hello everybody.

I owned an amp like this a long time ago, but sold it. I really liked it, so I found me another one.

however the new one doesnt have any power, the PWM gen chip is definately not a TL494. The chip identification has been purposely scrubbed off its face.

I measured a few pins with ic removed and matched a few physical traces, and the closest I can match is a SG2525 pwm controller chip.

can anybody help me confirm this chip? like if you have this amp and maybe your chip was spared of identification.

and this circuit is so nice, i just removed the ic and fitted in some IC sockets, so hot swopping or removing the ic is now a breze.

i have attached some pics, i hope somebody can help

Thanks everybody.
 

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I have done a few more checks, and it seems the 5.1v reg isnt giving output, i seriously think the chip is fried. because the 5.1v is absent then the pin 2 wont get pulled high, and pretty much everything else wont work. will rush over to supplier first thing tomorrow morning, and report back once i have fitted a new chip.

another thing tho, this amp is populated with 5 band blue color resistors, in some cases the resistors are daisy chained, I was thinking of repalcing all the saidy chains, but multimeter readings and color band calculations just dont add up, this is particularlay evident with mosfet gate resistors.

the strpes are RED BLACK BLACK GREEN RED, which i calculate as either 250ohm or 20Mohm, but then i read the resistor, with dmm outside the circuit, and it reads 150ohm.

im really confused about this, i dont know which values to go with, but then again the trusty 47ohm has always work perfect for me, and the drivers being BD139 amd BD140, im sure will have enough grunt to drive via a 47ohm gate resistor.

but some advice on the matter would go a long way in making me understand the circuit.
 
Use dummy loads. Dummy loads are a bit tougher than a speaker as a load so I generally test using 2x the lowest rated load for an amp. Test with music that occasionally goes into clipping.

I use the cylindrical ceramic wirewound resistors with forced air cooling from the end, through the resistors. The image below shows 2 of the 4 I use in series parallel so I can change the load by using one or two series pairs, connected in parallel.
 

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Hello Perry and the world, just aquick update on my Bass Audio amp, i replaced the PWM chip, i dont know which one it had, but i fitted a SG3525 and everything came to life, moving on to audio section now.

Because im going to frame this amp, there were a few resistors daisy chained at places (from factory it seems), so i bought correct value original 1% resistors and going to fit those in next.
 
this just me showing off lol, this precisely the point i decide if its a keeper or if its a seller lol, im keeping this one!

this amp came in with 300 ohm gate resistors and IRFZ44 PSU fets, it came with an assortment of output fets lol, presumably from a previous tech that hadnt a clue what he was doing.

i am going to fit it 47 ohm gate resistors and IFR3205 PSU fets, i want to use TIP35c and TIP36c as output fets but if anybody advises on a tougher more powerful fet i might go that route.

Hey Perry please advise on best output fets, output drivers comprises of MJE340 paired with TIP32c and MJE350 paired with TIP31c
 

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