Akai CR 80D SS: Bad Transistors?

QuadraphonicQuad

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senorverde

Active Member
Joined
May 5, 2016
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51
I have one of these on my bench right now which is causing me a whole lot of grief and has me positively stumped.

Overall the condition of it is pretty good. Heads are in good shape and there's plenty of miles left on the capstan. However when sitting idle (stop) it'll randomly make a hissy thundery noise which I attribute to bad transistors. During playback, I can hear the muting relays doing their job and sometimes music will 'click' in as it should. Other times it'll fade out and go silent during playback. The same is true when using headphone output. Oh, and it affects the VU meters too.

At first I thought some of the relays had cruddy contacts but banging a screwdriver on them didn't affect much. Then I thought maybe those play/record slide switches needed some Deoxit. Sprayed them, worked them, but no go. I want to say the problem somewhere in the muting/preamp boards. The only thing of concern is the power resistor on the 2/4 channel switch board getting a little toastier than what I think it should.

I'm hoping someone on here has some ideas before I lose my mind over this. I'm leaning on bad transistors since the problem is delayed and I've dealt with many Akai units of this vintage with iffy transistors. Any suggestions are welcomed.

Thank you!
 

Q-Eight

2K Club - QQ Super Nova
Since 2002/2003
Joined
Sep 30, 2003
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3,606
Location
Castlegar, BC, Canada
The story of my Akai 280 D-SS reel to reel is that I basically stole it on ebay for $50. It was even close enough to me to pick up and spare shipping. Luckily, it was in solid enough condition, electronically however was another tale. Back Left channel was flakey - just as you describe - static and thundering pops and occasionally would just fade to silence. I did manage to track down a reputable REEL-ONLY technician in my province who offered to give the deck the once over. He started with the bare minimum of just replacing bad transistors in the Back Left signal path, but during testing (HOURS worth) he found that the other channels would also get lightly staticky after time. Long story short, although we didn't change a single capacitor in the entire deck, he DID change out all the transistors. He did even mention that the transistors he removed are on a list of "known" problematic components. 5+ years later, my reel is still 100%.

Since they are both Akai-branded units, and from the same vintage, I would imagine they use the same components. Probably not a bad idea to seek out a tech willing to work on your unit and have him give it the business.
 
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