Recent content by bobob

Right, ordered a proper scope. Will take a while to get here so will report back! Thanks again

Just with a multimeter, I haven't got a decent oscilloscope unfortunately. Got a cheapy one I'll try with tomorrow.

Thanks @sweetbeats. I'll check the power rails again tomorrow, but it seemed ok when I did it over the weekend. Will double check again. Already tried swapping U403 out, but still the same. Think this might have been caused by a short. I noticed when I opened it up that the pad had lifted on...

It's on the control pcb assembly, mounted under the transport buttons. It's the one labelled CR400, with the white 6MHZ printed above. It's labelled Y400 in the service manual.

Picture:

It's the control pcb. It's labelled Y400 in the manual, it's CR400 on the board. The 6Mhz resonator. Hang on, will get a picture...

Bit more on this, when testing the oscillator at Y400, it's not giving a clear reading. Also it seems to be clicking in the mechanism for play sporadically when touching with the multimeter. I don't know whether that's because it's failed, or it's something else causing it.

Unfortunately not, no. It's like the buttons are completely unconnected. Traced the power as much as I can and it seems to be ok, but I'm a bit clueless when it comes to testing the functionality of the chips on there.

Hi all, My 388 has developed a fault, wondered if anyone could offer some guidance. The transport started acting a bit strange, play would only engage if I held down the play button for a few seconds, and now the transport is completely dead. The number display is still lit, but none of the...

Thanks very much, appreciate it. And yeah, on some of these pcb's there's more repairs than traces. Had a lot of work done to it over the years. Seems to be working a treat again now, so back to making music. Thanks again.

Fixed! The pads had lifted on P117 on the monitor pcb. Still only getting the right channel in the headphones, but think I can figure that out now. @sweetbeats Thanks so much for your help. No way I could have figured that out / had the confidence to figure that out on my own. Very much...

So, had a look at the meter PCB, I've got serial number 00 on my 388, so a lot of components / connectors are missing. Very hard to read the schematic as stuff doesn't match up. On the meter PCB there's no protection diodes at D301 or D302 on P108, so I imagine it's fried some stuff up there...

Sorry, ignore last post. Mixer channels are functioning fine now. Left channel is only out in headphones. Stereo signal playing fine through main outs. VU meters, channels are working perfectly. Stereo VU's are dead. Nothing at all.

Hey mate, thanks. Power's sorted, back to normal. edit - info correction.

Thanks for your help with this, it's very much appreciated. I got it back to Q100. Swapped it out, and also swapped Q101 while I was there, and we now have correct power. VU's aren't jumping, sound is passing through, albeit only the right channel (only tested with headphones, so might be ok on...