Motorola c-3000 Transitor

[krazyz1]

Need 4 Motorola C-3000 transistors for repair of Carver M-400 amp. I realize this is a " house number from carver " . Does any one know where I can purchase these parts , or what ACTUAL motorola part number is. On base the following numbers are stamped. "H41" and " 457 " . Any help or direction would greatly be appreciated. Thank you. krazyz1

[anatech]

Hi krazyz1,

Need 4 Motorola C-3000 transistors for repair of Carver M-400 amp.

Just use MJ15024 and MJ15025 to replace the NPN and PNP power transistors. Be very careful you don't break the transistor sockets. "Jiggle" as you tighten these, and before torque is applied. Make sure all the raised portions are through the holes. My pet peeve is getting one for service after the sockets are broken.

Use new mica insulators and fresh thermal compound, not for CPUs! Use less grease than was was originally applied. A thin coat on the insulators and transistors, a little thicker on the case work.

These amps are fun to service. What you need is a good memory and lots of patience. What you don't need is alcohol. A service manual wouldn't hurt either. Wish I had one so I could give you more exact help.

-Chris

[krazyz1]

Thats the problem. Don't know if it is NPN OR PNP. IT does make a difference!!!!! I DO have a service manual and just lists it as C-3000 - A carver house number. Karl

[wg_ski]

Collector is more positive than emitter for NPN, the other way around for PNP.

Originally posted by anatech
[BThese amps are fun to service. What you need is a good memory and lots of patience. What you don't need is alcohol.
-Chris [/B]

"Fun" in the sense that it is not . Especially if the power supply is the part that's acting stuipd.

[anatech]

Hi krazyz1,

Thats the problem. Don't know if it is NPN OR PNP.

You are kidding me, right?

If you don't know how to figure that out, there is no way you should be trying to repair any amplifier, never mind a Carver - and a Carver cube at that! These are not simple amplifiers.

No offense here, but if you were not kidding, STOP NOW!

I kid you not, if you are not very familiar with servicing amplifiers, do not proceed. If you will not pay to have it serviced properly, then give it to someone who will, rather than throw it in the garbage.

-Chris

[djk]

Ditto.

Plus, you should replace all the outputs anyway, not just the ones that have failed.

[kevvywevvywoo]

Isn't the Carver number on there to indicate they've been graded at the factory?

[wg_ski]

Originally posted by kevvywevvywoo
Isn't the Carver number on there to indicate they've been graded at the factory?

They were aluminum-cased TO-3's. This suggests they were prior to the widespread availability of the MJ15024/5, which were always in the TO-204. The originals were probably graded 2N5630/6030, which most other amps from that vintage with series connected transistors used.

[djk]

The original were Motorola MJ15015 and MJ15016.

If you really want the originals, I have them with late 70s date codes.

I would replace then all with MJ15024/25.

[wg_ski]

If they really were the 15015's, I would sure *hope* that they were graded! Stock units are spec'ed to the 2N3055 beta curve, which of course totally collapses before it gets to 10A. Bet that would cause a little distortion at 4 ohms or less.