Looks like this was asked before but need to ask again to be more certain. I'd like to repair this amp, but it needs new output BJTs.
Currently using SMW45N10 / SMW20P10.
What are my combinations/options?
IRFP9140 & IRFP140?
IRFP9140 & IRFP150?
I see a place in Florida may still have some IRFP9150 also.
Otherwise if there is no reliable part for this Cobalt 2100, its going to become parts unfortunately. I saw some repair threads where the voltages across emitters didn't look so great/reliable.
Currently using SMW45N10 / SMW20P10.
What are my combinations/options?
IRFP9140 & IRFP140?
IRFP9140 & IRFP150?
I see a place in Florida may still have some IRFP9150 also.
Otherwise if there is no reliable part for this Cobalt 2100, its going to become parts unfortunately. I saw some repair threads where the voltages across emitters didn't look so great/reliable.
Hmm found this strange distributor Sierra IC. Their site says they have thousands of each but you have to request quotation. Anybody ever order from here?
Sierra IC World Leading Electronic Component Distributor
Sierra IC World Leading Electronic Component Distributor
This may get you a little closer to an equivalent match
From Master Electronics Repair !: TABLE OF S SERIES TRANSISTOR EQUIVALENTS
From Master Electronics Repair !: TABLE OF S SERIES TRANSISTOR EQUIVALENTS
Attachments
Last edited:
Thanks but the sheet is referencing parts which are also obsolete and non-stocked unfortunately.
SMW45N10 ⇒ 2SK1382 2SK1434 (obsolete)
SMW20P10 => Not on the list
SMW45N10 ⇒ 2SK1382 2SK1434 (obsolete)
SMW20P10 => Not on the list
I've been using Vishay IRFP140/9140 in a Cobalt 260 that used the SMW20P/45N with no mods for over a year now. I have not used it for sub duty, but it sounds nice driving full range speakers.
Great to know the IRFP140/9140 are working in the 260, I have one I need outputs for. Just FYI for Dr Zeus, Arrow.com has both in stock. I just put some in my cart 🙂
I've rebuilt this amp.
For anyone looking, you may want to consider replacing the driver transistors in this or similar amp. Currently this amp is using MPSA06/56 and all the drivers are running hot as can be at idle. Even the original channel which I did not replace outputs/drivers are running so very hot for such a little transistor. I cant touch them for more that a about 3 seconds which is telling me about 150F+. I'm thinking those transistors are having some trouble controlling the larger than normal outputs and as they are running hot as heck; could have been the failing point of this amp I'm working with.
Coincidentally, I recently worked on an Orion NT200, which I believe was using similar large scale output transistors; and CENU07/57 for drivers.
For anyone looking, you may want to consider replacing the driver transistors in this or similar amp. Currently this amp is using MPSA06/56 and all the drivers are running hot as can be at idle. Even the original channel which I did not replace outputs/drivers are running so very hot for such a little transistor. I cant touch them for more that a about 3 seconds which is telling me about 150F+. I'm thinking those transistors are having some trouble controlling the larger than normal outputs and as they are running hot as heck; could have been the failing point of this amp I'm working with.
Coincidentally, I recently worked on an Orion NT200, which I believe was using similar large scale output transistors; and CENU07/57 for drivers.