Akai Reel to Reel help needed

Endeavor02

New Member
Recently my Akai Reel to Reel 1820d's audio has been fading in and out while the VU meter stays . This started happening recently but other than use it I can't think of anything I've done to it that would cause this problem and considering it's been functional for the past winter I'm starting to think it's a temperature caused issue now that it's warming up here.

I've disassembled the whole thing and replaced a capacitor (I had hoped was the problem but did nothing) but I haven't been able to find some of the things in the manual like the "POWER AMP. P.C. BOARD RC-589" although I think this is due to the manual being shared with the 1820 and 1820d.

I'm brand new to Audio DIY and any help would be greatly appreciated :)
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Yea these machines are very complex.

You would first need to determine whether the "fading out" is mechanical or component related. Ie: is it happening as the tape is intermittently losing contact with the tape head?

Does the problem happen in both channels? Does it happen more once the unit has been running for a period of time?
 
Yea these machines are very complex.

You would first need to determine whether the "fading out" is mechanical or component related. Ie: is it happening as the tape is intermittently losing contact with the tape head?

Does the problem happen in both channels? Does it happen more once the unit has been running for a period of time?
The VU meter consistently shows audio and you can hear in a very low volume with a lot of static when it fades out so I was thinking it was the amplifier card inside.
 
We need to see a schematic to see what's between the Vumeter signal and the output jack. you know the signal at the meter is OK.
 
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Not many things to check, if the VU meter shows a signal and the output fades, there is just one resistor between the vumeter and the output jack, and that transformer with the headphones output. It could be a cold solder at that resistor, but it would be at one channel at a time, not both channels at the same time.

What happens at the headphones out when you have this problem?

Try to discard a problem at your preamp or power amp.

Also, try to check if the problem happens when you monitor a recording signal too.

akai1820-d-output.png
 
Not many things to check, if the VU meter shows a signal and the output fades, there is just one resistor between the vumeter and the output jack, and that transformer with the headphones output. It could be a cold solder at that resistor, but it would be at one channel at a time, not both channels at the same time.

What happens at the headphones out when you have this problem?

Try to discard a problem at your preamp or power amp.

Also, try to check if the problem happens when you monitor a recording signal too.

View attachment 1184209
Thanks for the help! :)

The same thing happens when I use the built in headphone jack and if I feed out to my pre-amp through the back. The pre-amp ports are working properly, I'll try and record something tomorrow and get back to you with the results.
 
Thanks for the help! :)

The same thing happens when I use the built in headphone jack and if I feed out to my pre-amp through the back. The pre-amp ports are working properly, I'll try and record something tomorrow and get back to you with the results.

just monitor a signal from the input, even without recording it to a tape.

If the problem is at the headphones too, chances of a problem at that resistor, or solder on the transformer. I'd resolder all that "Output PC Board" as a first action. Then, if problem persists, I'd disconnect the Vumeter desoldering R1 and R2.
 
just monitor a signal from the input, even without recording it to a tape.

If the problem is at the headphones too, chances of a problem at that resistor, or solder on the transformer. I'd resolder all that "Output PC Board" as a first action. Then, if problem persists, I'd disconnect the Vumeter desoldering R1 and R2.
Sorry for late response,
When I put anything through the input with no tape on record, I get nothing. When I put tape through on record I get [Hum for 3 seconds -> static on right channel for 2 seconds] from both the headphone out and the out in the back of the unit. Any ideas?
Thanks
 
If the Vu meter doesn't show the problem, seems the problem is at that board. I'd do what described in the previous post: check resistors, and resolder.
 
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