my 250/250 mkii looks entirely different inside from the standard model. I upgraded the power supply to dual separate power supplies. All the transistors were upgraded to much better newer more linear transistors. And I mean all.
The internal wiring is all Cardas now. The speaker fuses are gone. Power cord seriously upgraded. Threshold style heat sinks added. Bias increased. Slow start circuit added.
I just bought a 250/250 MKII this week and there isn't that much information out there. It has RCA MJ15024 transistors. You upgraded to the MJ21194? I read a post from John Bedini where he recommended MJ15025?
Mine has dual transformers and 19,000 MFD 75V Sangamd capacitors, hard to read, I'm assuming those are power supply caps?
My amp has 75 mv DC offset on one channel, and it reads up to 22 v DC when you turn it on. Hopefully my tech can repair it without a schematic.
If it can be repaired I will try to do some mods to it. Can you tell me anything else about your slow start circuit? I think they sell them at DIY audio?
2 different Bedini 150/150 Mk II Amps
I was comparing the insides of another Mk II with mine and they are really different. The first one is like my old one with no markings on the transistors. John Bedini was supposed to do some kinda voodoo inside them to work his magic. I remember this detail because my ex-girlfriends daughter cooked that amp 30 years ago by playing it all day at max volume when she was staying home from school one day. My repairman was never able to get any details on those trannys so the amp was never repaired. I guess we can't post pics so I'll just have to describe it.I purchased a different new to me B150MkII recently and the insides are really different. All the trannys are labeled Made in Mexico and there are 4 new ones on the circuit boards along with other different components. The other amp didn't have these 4 extra ones or slots to install them. Everything in my amp looks very fresh and new although it could be just well kept. It sounds fantastic.
I figure there are 3 possible scenarios with my new amp:1.I had read that John Bedini had modified these amps during the run so perhaps I have a later version.2.I had read that JB also would do mods for you when you sent it in for service.3. A really skilled tech modified this with a new design and new circuit boards which I doubt.
Is there anyone out there who could help me out.Also the only thing wrong with mine is the little light in the power switch doesn't work or will sometimes flicker. I can't find the direct replacement so if anyone knows a source could you please let me know. ThanksBobber
I figure there are 3 possible scenarios with my new amp:1.I had read that John Bedini had modified these amps during the run so perhaps I have a later version.2.I had read that JB also would do mods for you when you sent it in for service.3. A really skilled tech modified this with a new design and new circuit boards which I doubt.
Is there anyone out there who could help me out.Also the only thing wrong with mine is the little light in the power switch doesn't work or will sometimes flicker. I can't find the direct replacement so if anyone knows a source could you please let me know. ThanksBobber