4 May 2013

Takamine AccurAcoustic Preamp Issues Part II






From 1992 - 1997.I was a Tech for a consumer electronic company.There were 3 mini department.There's the TV dept.(Television repairs).There's Video dept.(VHS,Camcorder repairs) and Audio dept. where I was in repairing mini hifi,cd players,anything that emits sound without visual gets through here.Though I don't repair TV and Video stuff I tend to occasionally became a fly on their wall.

Long story short most of the Takamine Preamp failure was due to leakage of all the electrolytic caps.Make sure you use a very tiny and sharp soldering tip to remove those caps.If you were to buy the same type of caps,make sure you buy more of it.Use or unused your preamp will cease and the caps will leak again in a year or two.Trust me.


My Thanks to Hugo Vilela from Portugal for the pictures above. 

11 comments:

Jon Land said...

Thanks for the guide on fixing this. I am about to attempt this on my own accuracoustic preamp. Can you recommend the best type (sound wise) of capacitor to replace the old ones with?

YusTech said...

You're welcome Jon,before you attempt going to the point of no return.You might need to consider a Hakko soldering that's equiped with motorist suction.
As for the capacitor base on my past experience I used generic smd caps for the work.I hope there's more reliable caps available now compared to then.
If you could,send me pictures of the result or share the link.
How about a like at FB.Haha.

YusTech said...

the hakko is needed should need to remove the slider pot.which are risky.forget that,use a tiny sharp tip iron.

David Chapa said...

I'm curious, when these preamps came in to be repaired, were the completely dead on arrival? I have the same preamp, and when I plug it in I see the green lights on the knobs, but get no sound when it is switched to EQ. However, when I switch it to PASS (bypass), I do get sound. Could this be the same problem you have described, leakage of the electrolytic capacitors?

Thanks

David

YusTech said...

David,
I have repaired several units long ago.Having been without a schematic at the time to go with I noticed the caps in all the unit has some visual cap leakage.I replace all and it works fine.So happens this the same for all units repaired prior and after.I'm sure your unit is as old as the ones I repaired.You could wait until it totally ceased to work.I suggest you replace first all caps before anything else.

I very much believe the caps has significant role in the preamp circuit itself .Maybe it doesn't interfere with anything else.I havent come across another acurracoustic in years now but I have received inquiry to repair two unit.Should it be mailed to me,I'll do a part III for this post.

David Chapa said...

Thank you for your response! I took it into my luthier, who is going to inspect it. If he determines it is a 'bad preamp', I will ask him for the old one so I can try to repair it myself.

Vince Legut said...

Hello
Do you fix these?
I have a dead one. Although I have not tried the pass switch yet.

YusTech said...

Yes Vince,I did fix a few in the past.Risky repair though due to tight space and repeat fault of the unit.Because of that I would say this one costly preamp to maintain unless you love so much.hehe.

Vince Legut said...

Thanks for the inspiration. After some inspection I believe my bad capacitor is the Sanyo 470uf 16v. I see leakage residue brownish on the board. Test with a meter indicates it's bad. Got 5 on order today. Since it's the big one on the edge of the board I think I can change it out. Hopefully a fix. I love this guitar. I'll let you know once I get the parts.

Ivan Chang said...

Hi,

Thanks for your post! It was very insightful. I was attempting to do some repairs myself. May i know how did you remove the pre-amp from the guitar itself?

Thank you!

YusTech said...

Hi Ivan Chang
If you cannot open the unit better send to someone who can.You'll do more harm to it if you poke around wrongly.

Thabk you.