i bought a bad amp and i replaced the p/s fets with irfz44n and one channel with 540/9540. and now the amp works but the repaired channel is distorted. does anybody know what could be causing this? several yrs ago i bought a repair cd from perry babbin and it was very informing. in fact so informing that several yrs later i'm still learning. haha. i've had a fair amount of success, ive repaired bad p/s, outputs, broken boards/traces, ect... but i still have problems with the smaller things (caps, diodes, transistors, ect). if anybody could help it would be great. the pics are of a 60hz wave 1 good 1 bad. i have all te equipment needed and quite a few parts on hand.
i havent lifted any parts yet but i see that a transistor 2a (q216) that is connected to d204 maybe burnt.
Check Qx12 and Qx13. You need to at least lift two legs so you can check for open junctions and leakage.
Did you confirm that the gate resistors and the source resistors are within tolerance?
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the big resistor (r263) connected to the source of the 540 is at 700 ohm all others are at 1 ohm. what size is that? i'll have to order some.
0.1 ohms, 2w.
While you have it out of the circuit, confirm that R261 and R262 are within tolerance.
While you have it out of the circuit, confirm that R261 and R262 are within tolerance.
i'm currenlty searching ebay for the resistors. is there a different place that you would suggest. i'm probably going to buy a bundle or a lot, i have a bunch of 1/4w and 1/2w but no 2w or surface mount.
thanks
thanks
Please only buy parts from reputable distributors (Mouser, Digi-key...). Too many people have had too many problems with ebay parts (particularly FETs).
do a lot of amps use the same 2w resistor? if so i'll buy about 25 if not i'll just get a few. what would you recommend for the surface mount? sorry for asking, it's just that sometimes i have trouble ans it makes me wander if i have the right parts.
yes.
71-CRCW080520R0JNEA
When looking for resistors, use the dimensions and the value and you'll generally get the right part. The dimensions are typically given on the site.
71-CRCW080520R0JNEA
When looking for resistors, use the dimensions and the value and you'll generally get the right part. The dimensions are typically given on the site.
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