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Topics - LMW93

Amplifier Discussion / Jazz Chorus 60 repair
April 14, 2024, 12:51:02 PM
Hello everyone!

I recently got a broken Roland Jazz Chorus 60 for cheap. It seems to be a pretty early model, because I couldn't find any similar ones by searching the web (pictures added). The previous owner told me that it stopped working like 20 years ago and that a friend of him tried to fix it with no results. two or three components are missing with burn marks on the circuitboard. Could be normal- or the fusing-resistors I think. I think he tried to exchange them, without changing the actual problem so he burned the circuitboard. I think it should be an easy fix to retrace the little burned parts of the circuitboard. But my problem is that I can not identify the missing components cause I'm not very good in reading schematics and identify the traces on the circuitboard.
The main problems which caused the components to burn out, are probably the old transistors so I ordered new ones.
for the 2SC1628Y I ordered a SC3503 and for the 2SA814 and the 2SC1624Y I ordered a MJE15030 and a MJE15031.
now my question is: has anyone seen this version of the Roland JC-60 and can identify the missing parts? and are the ordered transistors the correct replacement?

I've added pictures of the amp and the circuitboard plus a schematic for a different version of the JC-60, which seems ok for the power amp circuit.

thank you!