Hartke B60 schematic?


Friend of Leo's
Mar 31, 2020
oc. CA.
When we pulled down the Christmas tree lights this amp was forgotten up in the rafters.

I’ve looked on Safari and Google and can’t come up with a schematic.
If anyone knows of a link I would be greatly appreciative.

I tried what I thought I could read off of the transformer but the numbers and letters didn’t get me anywhere.

I’ve traced down the power cord through the fuse and the front panel switch and they are all working/un-blown.

When I get to the power transformer I’ve got continuity (and a nominal Ohm or 2 between the neutral and a Red- I’m guessing unused center tap? But I get no reading from the black lead to either of the other primaries.

I don’t remember who gave it to me but it looks like they probably used it for an extension cabinet, and possibly for a home stereo or something.

There was about 6 feet of thin speaker wire and a rather crude tape splice from the factory speaker pigtail.

I thought I would try to power it-Put a small patch cord between the effects send & return, possibly find out if there was either a preamp signal or a power amp signal but no dice.

I was thinking of plugging my pod go into it-it seems perfect size to play/sit in with old bandmates at a nice outdoor gig they have in Laguna Beach.

I don’t see any obvious trauma to the board top or bottom. There is one really cheesy part which is the little added board between the power transistors mounted to the large heat sink.

It’s flimsy as heck and I’m guessing the small transistor has broken from the traces on the bottom, by the way it waves in the breeze.

I’m guessing the power transistors are complementary, they don’t seem to be marked the same but the one on the lower right when viewed into the heat sink appears that it may have been heating and lost its numbers?

The two other larger transistors in the TO package Q11 and Q5 Appear to have maybe taken on a copper color around the edge, I don’t know if that’s from heating, but I’m sure I have some snap on heat sinks.

That little stand-off board really bugs me it just is so flimsy. I’ve seen things as add-ons on nicer namebrand amplifiers but they were mounted sturdy to standoffs.
Especially as this is a combo bass amp, I know it wasn’t going to be expected to fill a Colosseum, But I was out with a old English singer guitar player, and the bass player played something just like this, maybe double the wattage, and just took the feed out into the PAs and we did theaters in the round and large gigs on the East Coast up to 15,000 or more. Just The shaking of the risers alone would snap that thing off like a potato chip!

Any help - direction would be very much appreciated, i’m much better with tube amps.