- had peculiar oscillations which were solved by rerouting the internal wiring a bit
- redone a lot of solder points, I see it was previously tinkered with, so I corrected some spots
- swapped the master volume pot because it was bent in a way that caused issues and interruptions
- the first IC was replaced with one BurrBrown 2604 variant as it sounded better to me overall with it (tried others as well; also I don't understand why they chose 4558DD(!!) for all the stages as it has way too much gain but whatever)
- replaced the deep boost dpdt pcb switch as it didn't work at all, and didn't latch 95% of the time
- also tightened the speakers and grille, they were quite loose
Very decent sounds from this SS amp
A customer brought an RG1503 head to me for repair. The amp section is tore up and outputs have been removed. I think I can fixed or jump the bad traces but I need a schematic. Do you know where I might look for one or do you mind sharing yours? Thank you
ReplyDeleteHello, sadly I don't have the schematic (for my case, luckily I didn't need one).
DeleteI tried also searching all the corners of the web for one but couldn't find one for this model 😑. Aren't my posted pictures helping in any way?
Ultimately, you could simply email Randall, with pics of your issue and maybe they will supply the schematic.
Btw since you are doing this stuff (I actually stopped HGE Contraptions for others, it remained a hobby for myself, check out this insane Laney THD+SMD combo repair grrr: https://hgecontraptions.blogspot.com/search?q=Laney&m=1 )
Yes for sure! I wrote this reply but never looked at your pics. My store manager wanted 4-5 old amp projects put back together (they pre-date me) and this was one of them. They were all apart and sitting for about 5 years. I actually found a printed schematic after I wrote you but it calls for 6 outputs. My amp here uses a 4 transistor output like yours so the pics are perfect. Thank you!
ReplyDelete