80017A juno chip repair/replacement?

Hi all

I found a realy nice MKS7 roland rack locally ( basically juno 106 and TR707 in a box) and it works great …ALMOST

it has a voice chip that wont sound, in chord mode ( 4 voice poly) every 4th key is silent, and in whole mode ( 6 voice poly) every 6th key is silent

has anyone trued the acetone bath trick on a 80017A chip? or any other method of repair? Im in communication with the seller so he may just offer a refund in the meantime here is the acetone video, Im not going to open it up til I hear from him though

http://youtu.be/W4lF0xSVQlg

I’ve done the acetone trick. Works like a charm. It’s a pain in the ass though. It needs to soak for a looooonnnng time. Be careful with the pins. I had one snap off and one come loose. I was able to fix it, but it wasn’t fun. Also, adding sockets is a good ideer too.

Ok cool, any tips on desoldering the chip? just be careful and take my time? and how did you figure out which chip was which?

spring for an ultrasonic cleaner, that will clean the HELL out of it with acetone

Yeppers. Take your time. I did it with a solder sucker. My way was pretty dumb. It’s get as much out as possible then grab the chip and wiggle it back and forth. Any pins that didn’t move I heated up while continuing to wiggle. Eventually all the pins came free. Not recommended though. I was out of solder braid and too impatient to go and buy some more. I’d suggest removing them all. Better to clean every one and be done with it. The service manual should tell you which is which.

@altitude, I do need to get one of those. I’m tired of scrubbing flux.

you can find cheap ones on ebay for $40, very handy (the flux thing especially)

Yea i was thinking of doing all of them anyway , Ill wait and see what the seller tells me , I only paid 175 for it , and the bass , melody and rhythm sections work, just the chords dont , well 3/4 do :slight_smile:

Totally worth keeping and fixing.

I think I’ve replaced 5 voice chips in total in a friends juno 106. I used the Hakko 808 for that. Really easy to do, but maybe it’s cheating. :slight_smile:
I added some more solder to make it easier to suck the pins clean.

Is the bass section similar to the SH101? it sure sounds like it!

Last year I got Juno 106 with 4 flaky voices… used my trusty Hakko 808 (best investment ever!) to desolder all 6 80017A. Acetoned them for 4 or 5 days, carefully removing gunk every day. Some went clean after just two days, others took more. Eventually all were clean. 3 out of 4 chips work perfectly since then. One was still dead, so I had to order replacement from reliable source.

Ok cool! thanks for the info

The seller is giving me a 90$ refund, so Im only out 85 bucks , time to desolder some chips!

I always desolder multiple pins by just putting a huge solder blob across all pins. That way you can easily liquefy all at once. Easy to remove once the chip is off.

What about oxidation problem? If there is no plastic cover, it could be problem again in few month[?]. What are your experiences with that? Thanks

spray on conformal coating…

talk about resurrected threads! I need to get back on repairing this!

80017A in my 106 were acetoned more than a year ago and I don’t see any sign of oxidation, at least they are not any more oxidized than they were when the coating came off.

Ok Ive tried twice to desolder the 800 chips and cant do it, it seems my desoldering iron doesnt get hot enough :frowning: and Im terrible with the copper braid

Did they use diff solder when they made these? it seems really reluctant to melt.

I guess I could take it to a local electronics place and have em do it in a few minutes

Add some solder of your own first.