Desperately seeking Roland JC-60 schematic

[KilgoreTrout]

I'd greatly appreciate it if anyone could point me in the direction of a schematic for the relatively rare Roland JC-60 Jazz Chorus amp, only manufactured for a couple of years in the late 1970s. The "Roland Jazz Chorus" schematics readily available on the web are for one of the many versions of the JC-120. Thanks.

[studiologos]

did you ever came across does schematics?

[KilgoreTrout]

did you ever came across does schematics?

Unfortunately, no. I contacted Roland, who offered to sell the tech manual for $20 USD or so, but I declined.

- Kilgore

[J M Fahey]

Hi Kilgore.
$20 for the service manual is an excellent price, specially considering it's a rare and unavailable model.
If it saves you only 1/2 hour of bench time frustration, you're even.
Are you carrying it all the way to Trafalmadore?

[KilgoreTrout]

Hi Kilgore.
$20 for the service manual is an excellent price, specially considering it's a rare and unavailable model.
If it saves you only 1/2 hour of bench time frustration, you're even.
Are you carrying it all the way to Trafalmadore?

Good point. The original problem (hum) was resolved pretty easily (bad ground on the reverb pot), but I'd still love to have the manual. Perhaps I'll just become unstuck in time and order it.

- Kilgore

[TeeVeeFixer]

Good point. The original problem (hum) was resolved pretty easily (bad ground on the reverb pot), but I'd still love to have the manual. Perhaps I'll just become unstuck in time and order it.

- Kilgore

This should be it.

JC-60_60A_SM.pdf

[KilgoreTrout]

This should be it.

JC-60_60A_SM.pdf

You may be the greatest human being ever to walk the face of the planet! You have no idea how long I've been looking for this. Thanks so much!

- Kilgore

[Enzo]

Roland manuals and Yamaha manuals are excellent values for the money. Yes, free is always better, but these books include not only schematics, but also ALL specs, and all adjustment procedures and standards. Diagnostics are covered. there will be a complete mechanical blowup with all part numbers. In many cases there will be disassembly guides - especially useful for keyboards. Often as not there may be coverage for more than one variant within the manual.

All in all, I'd say that was worth $20.

[dsflores]

Hi, i hope to revive this thread. I have with me now a JC-60 and been looking for a schematics/service manual and eventually got here. I looked at the file posted by teeveefixer and somehow it shows a different layout with the actual amp i have. The one posted is for a single board only and mine has three boards (powerboard, effects board, and a combo preamp-poweramp board). All three are connected via wires with PCB terminals on edges of the 3 boards. From the file posted here, the power transistors uses flatpacks whereas my amp is fitted with to-3 sockets(the transistors are missing).

I am hoping for service manual for this type of JC-60. I think mine is an earlier edition. Many thanks in advance for the help.

[mozwell]

JC60, 60W output, missing TO-3 devices
You cant go wrong by using 2N3055 for the missign TO-3 devices (assuming they are both NPN types as in the service manual)
On your unit, check the drive transistors are the same as in the service manual (above), check the 0.33 phm resistors are ok in value, and check they connect to the speaker output for one, and the negative suppy rail for the other.
If the arrangement for your power amp is the same as in the service manual, then you should be fine using 2N3055. If the drivers are blown up, you can use MJE340 & MJE350 as replacements.

As the power transistors are out anyway, do you get all the proper power supplies, +/- 43V, +27V and +/-15V

With the TO-3 devices removed, and the amp powered up, do you get approximately 0VDC on the speaker output ?

[dsflores]

JC60, 60W output, missing TO-3 devices
You cant go wrong by using 2N3055 for the missign TO-3 devices (assuming they are both NPN types as in the service manual)
On your unit, check the drive transistors are the same as in the service manual (above), check the 0.33 phm resistors are ok in value, and check they connect to the speaker output for one, and the negative suppy rail for the other.
If the arrangement for your power amp is the same as in the service manual, then you should be fine using 2N3055. If the drivers are blown up, you can use MJE340 & MJE350 as replacements.

As the power transistors are out anyway, do you get all the proper power supplies, +/- 43V, +27V and +/-15V

With the TO-3 devices removed, and the amp powered up, do you get approximately 0VDC on the speaker output ?

Thanks mozwell for the quick reply. My dilemma is the wiring connections inside. some of the wires are missing or been removed. All 3 boards are connected in a point to point fashion. A picture is worth a thousand words so i must post them soon for us to see and it would be much easier.

As for the output transistors, i will take note of it. 2n3055 is a real workhorse and so are the drivers.

[DrGonz78]

Just came across this exact JC60 as mentioned in this thread. I too could not find the "exact" schematic, but all my wiring is setup correct. I figure that posting some pics might be useful for anyone who comes across this semi-rare version of this amp. I am currently restoring this amp to good working condition. Hope this helps someone on here one day if they have missing wires to each board...

[mozwell]

JC50 from 1983

[FobertRipp]

Hello, can someone reupp the Schematic for the Roland JC 60?

[KilgoreTrout]

Here you go:

https://drive.google.com/open?id=0B6...DFtbnNnaDV5T2c