Akai AA-1050 Power Issues??

[LJRuubles]

My lovely 1978 Akai receiver has a couple of issues. When hitting the power button the clicking sound that occurs a second or so afterwards that engages the speakers, won't happen. If it does happen the LED's start pulsing and a throbbing sound comes through the speakers in time with the LED flashing. This occurs on all outputs, aux, phono, FM/AM. What could this be and is it easily repairable?

Thanks!

 

[Punker X]

Moving to solid state. Not a "tuner" problem.

 

[mbz]

After power up, there is a delay allowing for transients to settle, before connecting the speakers.
This is done by protection circuitry. This circuitry also monitors the dc voltage level of the speaker
lines and if they are too high, it will disengague the speakers.

I had a look at the service manual, could not see the protection circuit/relay, but you description
matches this behaviour so I assume it was later added.

As a first guess, there is excessive dc on a speaker line caused by ageing/failing components
(transistor, capacitor,,,). This can be easily confirmed with a multimeter.

The Rxr is 40 years old, well past its used by date. It probably is in need of a refurbishment
involving,
- checking for dry solder joints
- recap
- setting bias
:

is it easily repairable

Depends how much time you have and how lucky you are.
First step would be to open the unit up and do a visual, looking for any stressed components.
Then check solder joints and wire connections are healthy. After that you will need to track down
the source of the voltage with a multimeter and probably replace 1-2 transistors. Not as hard
as it sounds. Yeah, I think the 1050 is worth the effort.

 

[sregor]

Just a shot, but sounds like you need to tighten the screws on the amp boards. There is usually one screw which grounds the board (Called a star ground) and if that is loose, get all kinds of strange noise and protection problems. If that is the case, usually a little deoxit and loosening then tightening should cure it. Hope this helps.

 

[Starbender]

Found one 1050 at the local thriftshop. It was on sale as 'for parts'. It has no outputs, no knobs, messy amp stage, filthy, dusty, rusty..

Someone messed up with this pretty hard and wrong as always..

After two weeks, it sings.. amazing sound..
Mine does not have any protection relay. Looks like there is another, revised version.

Check protection circuit. Its on the back side. Also check dc at the output. Also check bias voltage from the emitter resistors.

Repair if you can. Its really sounds wonderful..