Spec 4 Restoration Questions

[stdgrabbag]

Ok so I picked up a pretty rough shape Spec 4 and am planning on doing a restoration on it. So far I have taken apart and cleaned everything and have done searches and Found the BOM list from this site. so I am compiling my list if stuff that my unit will need to that list and getting my order together, but before I begin getting parts, I have a few questions.

1, Does any have or know where I can get a High resolution Schematic?

2, I see People mention about the Diode packs, One of mine is in good shape and another has had the legs broke off at the component body. I have been able to re-solder the legs back on the little stubs and the epoxyed over it so that they (hopefully) shouldn't come off. So with one Questionable should I stop the project or can i get replacements? the part # is 85C. I have checked it on a component tester on an Oscilloscope and not sure how its supposed to show, but my Fluke 83 meters Diode tester seems to show that it is working.

3, I need large Filter Capacitors, the most economical one I seen are at Digikey and they are the United Chemi con. Just curious what others have used and for fitment? value is 22000uf 80v.

4, It seems the previous owner sometime long ago in the past has had some repair/destruction done to the unit and it seems to have a random assortment of output transistors. I was probably gonna replace them with the ones you can get from Mouser, should i use those or try and find good original ones that I am missing?

Just for background on me, i have been an electronics Tech for the last 15yrs and have just recently gotten into vintage recievers and stereos, I own a Nice Marantz 4400 and recapped and own a Pioneer Sx 950. In my job I do a lot of component level trouble shooting and board repairs, so doing a repair job like this seems pretty straight forward, but quite costly.

Thanks for any help that can be provided.

 

[EchoWars]

1. I have a digital version of the scat, but it's the same thing you can get from all over the web. Nice to have for looking at whilst sitting at the computer, but when working I want the printed manual. The best are at Stereomanuals.com.

2. The remote-mounted multijunction diode is an STV-3H. As rare diodes go, this one is fairly easy to find. There's an eBay auction for one at a good price if you're worried about the one you have. Just make sure you install it correctly...it IS a diode and installing it backwards will mean the destruction of the output devices and probably a dozen parts on the driver board. (FWIW, a good STV-3H diode should read about 1.42V or so on most Fluke meters with the diode test).

3. Digikey has no 22K 80V UCC caps in stock. But they do have a 22K 100V UCC cap that I've used on many occasions. Part #565-3301-ND. It'll work great (but you'll have to enlarge the holes on the ground straps and the ring terminals, as the screws for the caps are a tad larger than stock).

4. Sourcing out-of-production Japanese transistors, especially TO-3 power devices, is a recipe for disaster. Replace the stock devices with On-Semi MJ21193G and MJ21194G. Might order some new mica insulators as well, Mouser part #534-4662, Digikey #4662K-ND. Order about 30 of them and pick the eight thinnest to use. Buy some decent thermal compound as well...Mouser part #567-120-2 (Digikey #345-1007-ND) is great (stir it up before using). Apply a thin coat to both sides of the mica insulator and slip it over the transistor, then install on the heatsink that you have previously cleaned of the old stuff. Doing this neatly is a challenge.

G/L

 

[stdgrabbag]

Thanks for the info, i check my digikey shopping cart and seen that i do have the 22k 100v in there, just got mixed up with the numbers.
Right before i went to bed i did find the stv-3h diode. Th3 same you posted and bought 2.
Thanks alot for the help, ill definitely pic ups some mica insulators for new transistors.