Music Man -HD-150R chassis 2275-150 new Power Transformer Wiring
For a missing Power transformer and Output transformers , Phil at Heyboer Transformers wound me a new PT based on the one they used to make for MojoTone - a 200-130 that replaces the 130 and 150 watt versions as noted in the MM Service Bulletin #3:
"200-130 Power transformer used to replace all 130 watt and all 150 watt having the "Hi Stby. Lo" switch on the front panel. (as opposed to "Hi Off Lo")"
The OT also matches the one that they made for MojoTone and was easy to wire in.
However, not having the original power transformer in the chassis when I acquired it, when removed by the previous owner the old transformer wires were clipped very close or de-soldered off of the chassis, so I have no corresponding reference for how to wire this new one in other than the schematic.
Also Service Bulliten #4 details Alternate Transformer Wiring of replacement transformers with a list of models that do not include the 2275-150 with the DB-4 solid state driver board.
So the question is - should I follow the original wiring scheme as shown on the 2475- 150, 2275-150 schematic or try the alternate wiring?
Anyone have one of these 2275-150s and some chassis pics that could point me in the right direction?
Link to service bulletins here on the site and the 2475-150,2275-150 schematic.
https://musicmanamps.net/sites/default/files/docs/MM%20Service%20Bulletins%20All.pdf
https://musicmanamps.net/sites/default/files/docs/2475-150_and_2275-150.pdf
Thanks
Micajah
Mid Century Audio

I took some gut shot of a…
I took some gut shot of a 150 I serviced but they really don't show much of the PT wiring. I'll post them if you want though.