Probably most likely has the " glue" issue.
CR-620 Woes
- Thread starter goldswimmerb
- Start date
So finding a replacement 2SB was easy, the 2SD seems harder. Would these https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/291825374419 NEC ones work? Or should I try to get Toshiba ones?
This for the M-40 or CR ?
CR-620, sorry.
Im assuming both pairs need to be swapped to the new transistors?
Not really.. Just the two on the shorted channel.
I'm assuming we'd need to adjust the idle current too?
After replacement of course.
So on the M-40 what's the best way to get rid of the glie? It looks like mine was later on the assembly line and the glue guy mostly gave up, but there's still a little there.
I just chip and scrape. It comes off real easy.
Alright, I got most of the bigger chuncks off, now there appears to be just a thin bit on the board and some near the two resistors in front and around the metal wire on the board. Once the glue is removed should I worry about replacing those resistors, and the metal piece, or since they're not completely destroyed will they be fine?
The only thing that turned greenish was the little copper divider (right under a very small but of glue), the jumpers are just white from minor corrosion. I think I dodged a bullet somehow with this $10 m-40 from Goodwill.
Those copper buss bars I remove and use Scotchbrite to remove the corrosion. Maybe hit them with a little metal polish as well.
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Hey, so progress report, new transistors arrived. Swapped everything out. We had it working for a bit, relay click and everything, idle current adjusted to 8mv+-2mv on each side. We were playing music through it too without issue. And then all of a sudden that resistor popped again. Any ideas what could cause that? We even swapped the shorted transistor out (T721).