Hi all,
I am fixing an audio research D-100B power amp. I think the output power transistors are dead. I don't know the part number printed on the transistor cover. What printed on the cover are motorola 300027 7926 and motorola 300026 7852. Apparently, they are complementary pair. I think the number is only for audio research interior reference.🙁
Anybody knows what they are??
Thanks alot!
Lhchen
I am fixing an audio research D-100B power amp. I think the output power transistors are dead. I don't know the part number printed on the transistor cover. What printed on the cover are motorola 300027 7926 and motorola 300026 7852. Apparently, they are complementary pair. I think the number is only for audio research interior reference.🙁
Anybody knows what they are??
Thanks alot!
Lhchen
If they are motorola in TO-3 cans you can bet they are MJ15003/04 or MJ15024/25. In any case either of these should drop right in and work identically.
Hi,
Thanks for the help. They use 6 pairs of pnp and npn power transistors in parallel to produce only 100 watts output at +55v -0- -55v voltage. So, it's very unlikely to be one of those that we often use. Those transistors must be out of production nowadays and long not availible.
I am looking for substitutions, still motorola ? no sanken?
Thanks for any coment.
Lhchen
Thanks for the help. They use 6 pairs of pnp and npn power transistors in parallel to produce only 100 watts output at +55v -0- -55v voltage. So, it's very unlikely to be one of those that we often use. Those transistors must be out of production nowadays and long not availible.
I am looking for substitutions, still motorola ? no sanken?
Thanks for any coment.
Lhchen
I am looking for substitutions, still motorola ? no sanken?
Yes, still Motorola/on semiconductor. No not Sanken if you want it to live for a while.
As mentioned by jaycee either of the motorola parts will work.
Yes, still Motorola/on semiconductor. No not Sanken if you want it to live for a while.
As mentioned by jaycee either of the motorola parts will work.
Sanken and Toshiba no longer produce meatal can T0-3 bipolar output devices. Motorola is almost the only source
These three companies produce very reliable transistors, but Sanken and Toshiba suffer more from fakes in the American and European markets
These three companies produce very reliable transistors, but Sanken and Toshiba suffer more from fakes in the American and European markets
Wait a minute!!
After I opened up the chassis, I found out 6 pairs of NTE60/61 each channel. We know NTE60/61 are equivalent to MJ15003/15004. My Audio Research D100b got only output at 100 watts at 8 ohm. At B+ as 55v-0v+55v, what would be the output rating? Where are those transistors from? Somebody put them in? For extra power?
Am I missing something here? Oh My! I bought a lemon.
Lhchen
After I opened up the chassis, I found out 6 pairs of NTE60/61 each channel. We know NTE60/61 are equivalent to MJ15003/15004. My Audio Research D100b got only output at 100 watts at 8 ohm. At B+ as 55v-0v+55v, what would be the output rating? Where are those transistors from? Somebody put them in? For extra power?
Am I missing something here? Oh My! I bought a lemon.
Lhchen
"Thanks for the help. They use 6 pairs of pnp and npn power transistors in parallel to produce only 100 watts output at +55v -0- -55v voltage. So, it's very unlikely to be one of those that we often use. Those transistors must be out of production nowadays and long not availible.
I am looking for substitutions, still motorola ? no sanken?
Thanks for any coment."
Why not use what Audio Research used?
The date codes indicate the 78~79 vintage, the MJ15022/23 was just showing up in amplifiers, that's probably what they are.
Take a dead one and cut the top off and look!
If not an MJ15022/23 they are most likely MJ15003/04.
I am looking for substitutions, still motorola ? no sanken?
Thanks for any coment."
Why not use what Audio Research used?
The date codes indicate the 78~79 vintage, the MJ15022/23 was just showing up in amplifiers, that's probably what they are.
Take a dead one and cut the top off and look!
If not an MJ15022/23 they are most likely MJ15003/04.
I am have asked to reopen this thread as I recently got an AR 100B also. I had the same question as djk, not sure if he still around, but I just removed the second driver board from CH2 and then had access to remove the heatsinks. Look like I have only 6 pairs of O/P transistors the 2 lower ones were never installed. It seemed AR must have had that chassis/board for possibly a higher power unit and they had 8 pairs of O/P transistors.
So that solves the mystery. I have to remove the 2 CH1 driver boards and the heatsinks to see what is under there. The first bank -far right of CH2 is what someone worked on to try and repair this years ago and then it sat for 10 years.
So that solves the mystery. I have to remove the 2 CH1 driver boards and the heatsinks to see what is under there. The first bank -far right of CH2 is what someone worked on to try and repair this years ago and then it sat for 10 years.
No, he’s not still around unfortunately. 3 pair per channel of 15003/4 are fine on +/-55V. That will give 100WPC out of a woosy transformer, about 140WPC out of a “good” one.