repairability of amps from the late 80's and 90's


Is it true that certain amps like Counterpoints, Fortes, and some other are difficult if not impossible to repair if their output devices should go bad. It is my understanding that they used IGBT (?) or particular MOSFET devices that are no longer made. Thanks.
Counterpoint amps can be completely rebuilt by Mike Elliot. Most other amps can be repaired if parts are available and in some cases modified if the same parts can't be obtained.
My friend owns a vintage repair service.He has told me that the Counterpoints amps used a transistor that is out of production,and that he won't touch the units.I imagine someone could rework them with another device,but I'm not sure it would be economically viable.My advice:steer clear!
Mikey can fix em.
It's true that some amps use MOSFETs that are simply no longer available, period. It's also true that most of Counterpoint's hybrid tube/transistor power amps used these things, too; as a result, if the output stages fail, they can't be repaired in kind. However, as Rwwear says, Mike Elliot will remove the old MOSFET output stages and put in entire new designs that don't use the MOSFETs. The practical result is that the unit is both repaired and upgraded. However, it isn't inexpensive - around $2K is the least it'll cost. For that price you use your existing case and a few parts but get essentially a new amp with a 5-year warrantee from Alta Vista Audio (Elliot's new company).

Counterpoint also made at least one other power amp, notably an OTL model (the SA-4), and this is fully repairable in kind.

Finally, they made all sorts of tube preamps, line stages, phono stages and MC step-up devices, all of which are fully serviceable by Alta Vista. The repairable items are pretty economically feasible. One of my amps was repaired in this way by its previous owner.

Alta Vista also offers upgrades on most Counterpoint gear. In my experience, these are expensive but result in excellent sound, as they basically update really good pieces from the 80s and 90s to current designs. There are limits, but I've been surprised what can be achieved within those limits.
Service is available for Threshold/Forte from a highly qualified former employee at reasonable rates.
Thanks everyone who has brought some clarity to me regarding this issue. It is good there are still resources out there to take care some of these amps. With the Counterpoints, it sounds like it may lead to an expensive path.

I cannot use the URL in your post. Are you sure that is the URL? Thanks, RM

Your URL is correct. Don't know what was going on last night.