Quote:
Originally Posted by ben
Thanks for the responses. The s/n is 2216252, so fortunately has the later design.
The board is not the most pleasant to work on - no component numbers at all, and whilst the print side is easily accessible, the same cannot be said for the component side. I will try to make some kind of a jig to be able to run the unit out of the case.
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Yeah, the 12 is really annoying in that there are lots of small spade connectors to the amp board which must be removed to work on the component side and of course carefully replaced so they are all in the right place after reassembly. This is in contrast to the 1200X where I think there are large connectors so you remove a couple of plugs and you're done. There's still the linkage to the speed selector switch and rec/pb switch though of course.
On the later 12's, the component layout is somewhat confusing in places as it's the same PCB as the earlier version, which leads to some component holes being unused and some components being mounted in seemingly odd positions if I remember correctly.
I'd still recommend signal tracing rather than replacing each component until it works.
Thinking about it, one problem I have with my (late serial no) 12 is that sometimes the channel 1 rec/pb switch in one of its positions doesn't always make the proper connection so the channel is silent. Don't have the machine in front of me right now so I can't verify exactly what it is that doesn't work properly, but jiggling the switch back and forth a few times yields a position where it works. It seems to get better with use. Quite possibly not an issue on the OP's machine as the contacts have been cleaned, but the little contact springs and associated contact rings can be finicky to adjust if they get bent so I though I'd mention it nevertheless.