FINALLY, something different. This failure was not one I have seen before. C31 appears to have prematurely evacuated and caused all sorts of issues. Z2 was toasted, Q5 evaporated and R51 failed. The BASH board was taken out as well with a blown diode, transistor and the IC. The IC's are a pain in the *** to replace because of the glue or epoxy used to try and hide the UC3842 chip. The board did have some damage to the copper plane under the cap, probably from the electrolyte. This is a fairly easy spot to repair.
Best guess, Q5 failed and took out the bash board and caused Z2 to fail. R51 then failed from heat due to the current draw. When the bash board stops working the voltage on C31 goes over 100V, which it is only rated for and that would cause the leakage. Normal voltage is around 90V. This is why on later revisions this cap was upgraded to a 160V version. It is still OK to use a 100V cap here, as long as the amp is working properly. Go 160V if you want to play it safe.
As usual, glue removal and Q5 upgrade with a full recap.
Hi, I am a newbie but my sub started humming for a while (several minutes) upon powering up so I decided to crack it open, mostly to satisfy my own curiosity. It's a different model (old PSB Subsonic 5i) but it does have the big yellow thingy that can be seen at the top of the first pic of the quoted posting, the one with the text printed on top "indigo xxxx Rev. B xxx". In fact I think it may be the same part. On mine, however, it seems to have leaked a brown resin like goo all around and there's some browning on the underside of the circuit board, presumably as a result of the ooze.
My questions are, 1) what is this component called? 2) Is the brownish ooze indeed from the failure of this component? 3) If so, can I simply buy this component and replace it myself or am I biting off more than I can chew as someone who just knows how to simply solder things on a board?
Sub-10 / Sub-12 / RPW-10 Repair Blog
in Technical/Restorations
Posted
Hi, I am a newbie but my sub started humming for a while (several minutes) upon powering up so I decided to crack it open, mostly to satisfy my own curiosity. It's a different model (old PSB Subsonic 5i) but it does have the big yellow thingy that can be seen at the top of the first pic of the quoted posting, the one with the text printed on top "indigo xxxx Rev. B xxx". In fact I think it may be the same part. On mine, however, it seems to have leaked a brown resin like goo all around and there's some browning on the underside of the circuit board, presumably as a result of the ooze.
My questions are, 1) what is this component called? 2) Is the brownish ooze indeed from the failure of this component? 3) If so, can I simply buy this component and replace it myself or am I biting off more than I can chew as someone who just knows how to simply solder things on a board?
Any guidance would be greatly appreciated.