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.
18 comments:
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?
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.
the hakko is needed should need to remove the slider pot.which are risky.forget that,use a tiny sharp tip iron.
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
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.
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.
Hello
Do you fix these?
I have a dead one. Although I have not tried the pass switch yet.
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.
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.
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!
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.
I've a takamine santafe ltd 97 who have an accuracoustic eq. The volume is poor.Can I check somebody who repair or is complited death. Thank matteo
Matteo,
Check with your local repair shop and ask them to replace all six tin can caps shown in picture.
Thank you
Hi,
Thanks for your useful post.
I have Takamine GB7C with Accuracoustic preamp. Sound was very poor 3 months ago. Now, when I pressed battery-check button, I can see leds are lighted on the knobs. But, no sound even with a new 9v battery.
Is it possible to repair it?
Or, what is the best alternative preamp to replace it to the same hole? Because, I don't want to broading the hole.
You can send your suggestions to also ahmet.ozeren@yahoo.com, I'd be appreciated.
Sincerely
I read this post long ago and passed it on to a friend who repairs electronics in Louisville KY. He has since fixed 6 preamps for me so far, and many more for others. If anyone is need of having their AAP repaired, come over to Facebook.com/groups/takamineguitars and find more info there.
Don't know if you ever got your preamp fixed, but read my comment below yours if you still need help.
I had fixed a coupled in the past. Thank you sir.
Hello, great information here, thank you! I have a 1998 Ltd Takamine that came to me with an accuracoustic pre amp. This pre amp still works fine except it does not have much volume output. It’s still acceptable but I have to run it with volume full out to get a decent signal. Years ago I bought a CBT-4-II pre amp that fits the frame perfectly and has been working well. It’s output is very hot and I cannot run it with the volume control more than about 35%. I’ve also found that it produces an electronic hum with several of my amplifiers and have recently gone back to the accuracoustic. So, for the person that wanted to replace the accuracoustic, the CBT-4-II fits well as a replacement. Cheers
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