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Akai GX-260D transistors

Agmed94

Agmed94

New Member
Hello All,

This is my first post so please go easy on me.. I recently came to acquire an Akai reel to reel (model GX-260D). It appears to have transistor issues similar to those reported in many AK threads. The problem manifests with poor sound quality in the left channel (a scratchy/distorted left channel sound, an erratic/bouncy left channel VU meter, and the left channel cuts out all together intermittently).

According to the service manual, this model does NOT have the notoriously faulty 2SC458 transistors. Instead it shows to be equipped with 2SC711's and 2SC1312's.

Are the 2SC711 and 2SC1312 transistors causing similar problems as the 2SC458?

Both are discontinued. I've shopped around for replacements and find the 2SC2910 is listed as a substitute for BOTH. If I proceed with replacement, it will be a total of 25 new 2SC2910 transistors used to swap out the existing 2SC711's and 2SC1312's in the boards for the play-back and record amps. (I am aware the pin out is reversed for all the new 2SC2910's)

Am I on the right track? Thanks in advance for your help.

I LOVE this machine and will be heart-broken if I botch this job.....
 
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I have one. I loveit. I'm rebuilding a 370D at the moment, which uses those transistors, so instead of still using ancient ones, I'm going with KSC388CYTA in place of 2sc711. I don't have any 1312s but if they are close to the 711s, you could just use the KSC388CYTA for them, too.

Good luck! Make sure to deoxit all volume controls first to eliminate variables. I haven't replaced the transistors in mine and it still sounds great. The 458s are the really problematic ones.
 
Hmmm...
Great info, thanks! Definitely looks to be superior transistor but way more expensive ($.40 vs. $2.36 each). I appreciate your advice. In your opinion they are worth the premium price?

This adds another $50 to my project. I'm going to have to break open my piggy bank!
 
Agmed94 said:
Hmmm...
Great info, thanks! Definitely looks to be superior transistor but way more expensive ($.40 vs. $2.36 each). I appreciate your advice. In your opinion they are worth the premium price?

This adds another $50 to my project. I'm going to have to break open my piggy bank!
Click to expand...

Where are you getting your transistors from? I just checked mouser and both the transistors Avionic listed as well as the one I listed all cost under 25 cents.
 
Agmed94 said:
....a scratchy/distorted left channel sound, an erratic/bouncy left channel VU meter, and the left channel cuts out all together intermittently
Click to expand...

iloveamps said:
Make sure to deoxit all volume controls first to eliminate variables.
Click to expand...

Make sure you follow iloveamps advise & clean all the controls and switches first.

This is a much more likely fault than transistors and will cause exactly what you describe.

Ron
 
Thanks everybody. I'll definitely do the cleaning first. I'll be so happy if that's all it takes. I'll let you know soon.

BTW, I was getting those prices from MCM electronics website.

Thanks again!
 
Agmed94 said:
Thanks everybody. I'll definitely do the cleaning first. I'll be so happy if that's all it takes. I'll let you know soon.

BTW, I was getting those prices from MCM electronics website.

Thanks again!
Click to expand...

Go with Mouser out of Mansfield, TX. MCM is way to expensive.
 
Just a quick follow-up... Still not fixed. It appears coffee or similar was spilled into the unit from the top. I don't see any damage or evidence of the spill except for corrosion in the corner of the bottom plate and some drip marks. I used de-oxit on all the level controls and switches. I also cleaned the heads/guides/pinch roller (they needed it). Anyway, all to no avail.

Total bummer! :( Sad part is it was working fine for the first 2 or 3 reels I played after first plugging it in. Ever since then the left channel bugged out and continues to be a mess.

I think I'm realizing this is a bigger project than I'm capable of handling.

Sadness...
 
What happens if you change directions a few times and try again? You might have a signal relay with oxidized contacts- cycling between fwd and rev might make it work again for a little while.
 
check the record/play switch, probably big long slider with lots of connections, this would be my first place to look when I have any problems with any kind of tapedeck
 
Can't find replacement capacitor..

Another quick follow-up.. I dug in a little further and found a blown capacitor (see attached picture, you can see the end blown off where the tooth pick is pointing). Anyway, I've had no luck finding a replacement. The service manual describes it as: "MP Capacitor, .1 uF, 350WVDC". It's about the size of an N cell battery, the part# is EC273464. I can't find it anywhere. Any ideas?

Thanks in advance!
 
It's an axial .1uF, 350V capacitor. I can't tell from the photo if it's a polarized electrolytic, NP electrolytic, or film cap. Not sure why that would be difficult to find.
 
Those look like the same ones in my X-355 :(
bad_cap.jpg
 
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