Request for Roland JC60A Service Manual

[dsflores]

I am looking for a Roland JC-60A 1977 Service Manual or better all JC60 versions.

Thanks in advance.


Deni

[mozwell]

i hope this helps

[dsflores]

i hope this helps

Thanks mozwell. i had it checked. it covers roland 1979 and 1983 models with serials starting with 7xxxxxx and 8xxxxxx. Mine is a 1977 edition with serial number 696231.

The effects board is separate from the preamp and poweramp combo-board. Still a big thanks mate! Would try to see with the similarities with the amp.

An honest mistake i guess from the thread title...it should be ROLAND JC60 1977 Service Manual request.

cheers!

[DrGonz78]

I have that exact same amp and could never find the correct schematic. I looked forever and gaveup, actually still keeping an eye out. What is the problem with the amp? I had problems with a couple resistors burnt out on the preamp board. I basically got really lucky and CSI'd the burnt resistor color bands. I recapped the entire power board supply and the amp sounds amazing! If you really need the help with this amp I have a working one to reference if it comes down to that approach. Just let me know if I can help in any way, good luck! Also, I am reattaching some old pictures of the board(s) layout gut shot. I had these pics on here before but there was a server crash that deleted them...

[DrGonz78]

Does this look like the amp you have in question? Preamp board, effects board, and power board. I took these pictures just to show all the wired connections on all the boards in case it ever helped anyone else.

[dsflores]

DrGonz78, yup that is how it looks. The wires were messed up. power transistors are taken out, TO-3 type. Newer transistors can be substituted as far as i know. At the preamp/powerboard, a 6-pin transistor is missing. Deducing from several jc120 schematics, its a FET-matched pair in a single case. Time to take pictures of it Doc....let me get back to you....

[dsflores]

here are the insides:



obviously, last person who touched it made some markings but were not followed just the same. some parts were replaced and some are missing in the power amp board. anyways, i would love to bring this thing back to its working state.

[Jazz P Bass]

Stereo Manuals .com seems to have one in your serial number range.

"Roland JC-60 Guitar Amp Service Notes #1 (1977) (Jazz Chorus 60) (Serial #512400 and up) Also JC-80 (Serial #510950 and up), JC-120 (Serial #510850 and up), JC-160 (Serial #512500 and up). Provisional Manual. G6 ROLJC60-SM1 20 total pages (2 intentionally blank), constructed as the original including almost entirely 11in x 17in folded /trimmed pullout pages, card stock covers, neatly assembled with 5 staples and fiber reinforced taped spine. Models covered: JC-60 (Serial #512400 and up), JC-80 (Serial #510950 and up), JC-120 (Serial #510850 and up), JC-160 (Serial #512500 and up). The original has a few small areas of faint print and it is printed on thin semi-translucent paper which makes it nearly impossible to improve upon. Overall quality: 10% Fair, 90 Very Good.

Roland High Quality Service Manuals User Owner Instruction Manuals Schematics Brochures Literature Printed PDF (some FREE)

Looks like $9.00 US.

[doctor]

Stereo Manuals .com seems to have one in your serial number range.

"Roland JC-60 Guitar Amp Service Notes #1 (1977) (Jazz Chorus 60) (Serial #512400 and up) Also JC-80 (Serial #510950 and up), JC-120 (Serial #510850 and up), JC-160 (Serial #512500 and up). Provisional Manual. G6 ROLJC60-SM1 20 total pages (2 intentionally blank), constructed as the original including almost entirely 11in x 17in folded /trimmed pullout pages, card stock covers, neatly assembled with 5 staples and fiber reinforced taped spine. Models covered: JC-60 (Serial #512400 and up), JC-80 (Serial #510950 and up), JC-120 (Serial #510850 and up), JC-160 (Serial #512500 and up). The original has a few small areas of faint print and it is printed on thin semi-translucent paper which makes it nearly impossible to improve upon. Overall quality: 10% Fair, 90 Very Good.

Roland High Quality Service Manuals User Owner Instruction Manuals Schematics Brochures Literature Printed PDF (some FREE)

Looks like $9.00 US.

Here are the service notes.

DrGonz78, don't despair and never lose hope.
Dsflores, good luck.

[dsflores]

Finally, thanks for the "prescription" doctor! What a wonderful way to spend the upcoming days before new year in restoring this baby.

Many thanks a lot...

[dsflores]

Hi, Doc! Finally this is what i came up with the power section for the JC-60. Its been quite a year-long restoration. I had it done just before New Year's eve.

Click on the link for details:

L.E. Amplifiers: Roland JC60 with LE Series 2 BJT

Power amp module details are here:

https://docs.google.com/leaf?id=0B98...uthkey=CMaYoHE

or here:

https://drive.google.com/file/d/0B98...it?usp=sharing


A blessed new year to everyone!

[drewl]

Arise ye thread of old!

Working on one of these that has a bad Q20, the dual FET labeled E-412

Funny, it's missing in the amp dsFlores is working on in the pix above!

Signal ends there, if I jumper across it with a cap amp works fine putting out plenty of power, I guess it's being used as some sort of limiter circuit?

Anyone have any idea what type of FET it is?
I'm sure I can use two single FETs

The exact version is in post #9, the middle one linked by doctor.

[dmeek]

Here is the datasheet

[drewl]

Oh wow!
Thanks very much!

[g1]

I guess it's being used as some sort of limiter circuit?

Anyone have any idea what type of FET it is?
I'm sure I can use two single FETs

The exact version is in post #9, the middle one linked by doctor.

Usually dual Fets are used when precise matching is required. Not sure what this one is doing, there is VR11 trimpot there to adjust something. Complete service notes would probably include VR11 adjustment, which would give an idea what the dual Fet is doing.