AKAI M8 recapping

[Welsh Anorak]

Luckily I had a scrap deck so all was well.

A little investigation should help find the VU problem. I assume it doesn't register in play or record? If that's the case using a digital meter measure the meter's coil resitance - it should be a fairly low ohms reading. Hopefully that will be OK and you can move to the meter drive circuit. There's not much there so if you're lucky it'll just be a wire that's come adrift.

[RoyceVM]

Glad to know you found a replacement part for the cams. If not, I would have looked for one here in US.

The right VU don't move at all in play mode. I never checked in record mode because I have to buy the RCA to line in connector to try that. I bought an ADM 11 microphone and soon I receive it will try recording with it.
If I remember correctly, both read around 500 ohms. I will check the line connections. Thanks!

Motor temperature is not exceeding 110F after 40 min playing. I hope that is fine!
I think that is something I need to watch. It is better to replace the motor caps if the motor slows down or overheat.
In the schematics I somehow missed the value of those capacitors.

[RoyceVM]

Found the motor caps C30a and C30b, they are 2.2 µF 300V and 0.5 µF 300V film capacitors. Motor is running with correct speed and no overheating at this time so, I would leave them alone.

[RoyceVM]

I gently tapped the right VU meter with my finger when it was playing music, and it jumps as I tap but not responding to the audio. So, needle assembly is not stuck. So it seems like it is not getting any voltage.

I had the same issue with boomboxes where VU sometimes don't respond and the major cause was always a dirty record bar switch. A good cleaning of that record bar rectified the problem.

I cleaned the record switches with DeOxit FaderLube 5 multiple times (50 reciprocating movements each time) and believe it is all clean. After all this M8 was extra clean to begin with. L

[DMcMahon]

Originally Posted by RoyceVM

Found the motor caps C30a and C30b, they are 2.2 µF 300V and 0.5 µF 300V film capacitors.

Looking at the M8 Service Manual there appears to be a small error/discrepency in relation to the motor capacitors.

On page 19 exploded view it shows a component that looks like a can capacitor, with item # 83-001m. On page 13 Drive Motor Parts List section, item 83-001m is described as Condenser 2.2u + 0.6u

On page 22 schematic motor capacitors are shown as C30a 0.6u C30 2.2u

So from the above, item 83-001m looks to be a dual can capacitor C30a + C30b

The error is that also on page 19 a single capacitor is shown fitted across a 3 way terminal strip identified as C30a. I think most likely this capacitor is actually C29 0.5uF which is switched in to the motor circuit when high speed is selected.

The motor capacitors C30a & C30b are listed as M.P. (Metalised Paper) so not film capacitors originally.

David

[RoyceVM]

Originally Posted by DMcMahon

Looking at the M8 Service Manual there appears to be a small error/discrepency in relation to the motor capacitors.

On page 19 exploded view it shows a component that looks like a can capacitor, with item # 83-001m. On page 13 Drive Motor Parts List section, item 83-001m is described as Condenser 2.2u + 0.6u

On page 22 schematic motor capacitors are shown as C30a 0.6u C30 2.2u

So from the above, item 83-001m looks to be a dual can capacitor C30a + C30b



The error is that also on page 19 a single capacitor is shown fitted across a 3 way terminal strip identified as C30a. I think most likely this capacitor is actually C29 0.5uF which is switched in to the motor circuit when high speed is selected.

The motor capacitors C30a & C30b are listed as M.P. (Metalised Paper) so not film capacitors originally.

David

Thanks David!