I'd suspect one of the two diodes is open on the other supply. Disconnect them both and test them with an ohm-meter. Of course, bad caps can also cause this kind of problem too.
The 9.6V regulator gets its input power from the raw 14VDC supply, so you can re-use that part, even if you just mount it on a blank panel. The Micor exciter power control (IPA) operates from the 9.6V supply, so I'd think it needs to provide several amps. Astron only uses the positive half of the diode bridges in their supplies, so you can certainly use the negative half in the Micor supply. It may be more expensive or harder to find a two-diode array with that much current capacity. I agree; OEM parts are certainly desirable, especially when you can see tham all the time (like front panel escutcheons and knobs), but you have to decide what your priorities and goals are. Articles are always good. Bob M. ====== --- On Thu, 9/18/08, kk2ed <[EMAIL PROTECTED]> wrote: > From: kk2ed <[EMAIL PROTECTED]> > Subject: [Repeater-Builder] Re: Micor TPN1110A power supply parts ID > To: [email protected] > Date: Thursday, September 18, 2008, 2:33 PM > Thanks for the reply, Bob. > > It sounds like the 50a bridge rectifier may be my best bet. > Same > with the newer style caps. > > I'm admittedly somewhat of a perfectionist and neat > freak, and my > motto has always been "use oem parts for proper > repair", but this > appears to be one of those cases of "do you want it > fixed or not?", > and I guess an ugly working TPN1110A is better than a junk > TPN1110A! > > I will hit eBay and pick up a few of the bridge rectifiers. > A screw, > nut, and some thermal grease and that part should be good > to go. The > caps, well some heat shrink and wire ties should fit the > bill. > > I have a second TPN1110A that works but has horrible > voltage sag and > ac hum under load. So I guess I will be rebuilding two of > them at > once. > > Maybe a few pictures and RB article are in order when > I'm done. > > > Eric > KE2D > > > > --- In [email protected], "Bob M." > <[EMAIL PROTECTED]> > wrote: > > > > Other diode alternatives: consider replacing the two > diodes with a > bridge rectifier. You can get a 50A 1000V unit (I've > used these in > Astron RS35 supplies) on eBay for about $5 - KBPC5010. One > single #8 > machine screw holds it to the chassis, and 1/4 inch > quick-disconnect > terminals let you connect it to just about anything. There > are also > 60A and 70A versions on eBay. You'll need to add your > own ground wire > to the negative terminal, but it's probably easier to > deal with in > the long run. > > > > Stud diodes come in both anode-to-case and > cathode-to-case, but > they're each about the same price as the bridge > rectifier, and you > need two, plus some means of mounting them (bracket etc). > > > > I guess you have to decide if it's worth replacing > just the press- > fit diodes to maintain the original Motorola configuration, > or > finding a current component that will do the job and be > readily > available if it ever fails again. > > > > Bob M. > > ====== > > --- On Thu, 9/18/08, Bob M. <[EMAIL PROTECTED]> > wrote: > > > > > From: Bob M. <[EMAIL PROTECTED]> > > > Subject: Re: [Repeater-Builder] Re: Micor > TPN1110A power supply > parts ID > > > To: [email protected] > > > Date: Thursday, September 18, 2008, 1:02 PM > > > Those big aluminum electrolytic caps with screw > terminals > > > are getting extinct, and if you DO find one, > it'll > > > likely be expensive. You can get something quite > smaller in > > > size but the same or larger electrical value. Go > with that. > > > Stuff some stiff foam rubber or even some wood > slats around > > > the bottom so it will fit into the original > clamp. > > > That's what a lot of the hi-fi repair guys > are doing > > > now. A lot cheaper for something that has much > better specs. > > > > > > The diodes are probably very similar to what an > automobile > > > alternator uses. Of course, finding the exact > replacements > > > could still be difficult. They're probably > (minimally) > > > 50V, 50A, but I'd look for something a bit > bigger. The > > > supply is good for 25A at 14V nominal. According > to the > > > schematic, the anodes (the ends with the arrows) > are > > > connected to the case and ground. Push-in diodes > came both > > > ways, mainly because many alternators use three > of each > > > inside, and they can only ground the case of > three of them. > > > > > > You could also replace the diodes and bracket > with a piece > > > of aluminum heatsink material and use stud-mount > diodes. > > > Again, observe polarity otherwise you'll have > to > > > insulate the cases or the heatsink (probably not > a good idea > > > to have that sitting at +15V). > > > > > > Bob M. > > > ====== > > > --- On Thu, 9/18/08, kk2ed <[EMAIL PROTECTED]> > wrote: > > > > > > > From: kk2ed <[EMAIL PROTECTED]> > > > > Subject: [Repeater-Builder] Re: Micor > TPN1110A power > > > supply parts ID > > > > To: [email protected] > > > > Date: Thursday, September 18, 2008, 10:10 AM > > > > The diodes CR1 and CR2 are > compression-fitted style > > > > rectifier diodes > > > > that are pressed into a rectangle stock of > aluminum, > > > and > > > > the aluminum > > > > is then secured to the chassis via two > screws. The > > > diodes > > > > have one > > > > solder lug terminal. > > > > > > > > The service manual only lists the Motorola > part #; no > > > specs > > > > or > > > > industry-standard part # is given. Same on > the caps. > > > Only > > > > spec given > > > > is 27,000 uf @ 20wvdc. > > > > > > > > I did a quick search of Mouser and DigiKey, > and was > > > unable > > > > to find > > > > any chassis-mount style caps. Anyone find > something > > > > suitable that can > > > > be re-secured to the ps's chassis via > new rivets > > > or > > > > screws? I know I > > > > can just solder in any cap that meets > electrical > > > specs, but > > > > I would > > > > like the caps to be secure and not have the > ps become > > > a > > > > fire hazard > > > > waiting to happen! > > > > > > > > The power supply was still sitting in my > truck last > > > night. > > > > When I get > > > > a break today I will take it apart further > and see if > > > I can > > > > find a > > > > part # stamped on the diodes and caps that > might > > > indicate > > > > what the > > > > real part # is. While I was at the repeater > site > > > yesterday > > > > I thought > > > > I saw a 1Nxxxx stamped on the diodes. > > > > > > > > I would have thought that there would have > been > > > someone > > > > here on the > > > > list that has repaired one of these supplies > before, > > > so > > > > that is why I > > > > asked. > > > > > > > > Eric > > > > KE2D
