Motorola Power Supply Info Needed

[Tom in D.C.]

I'm trying to help a local repeater group find information about a
Motorola power supply that's listed as a Motorola TPN1217B43.
Unit is reported to be putting out 17VDC no load and about 15VDC under
a moderate load.

Photos can be seen at:

http://picasaweb.google.com/Daniel.H.Br ... EDuCrXf4WI

All help, leads, etc. appreciated.

[Dan562]

Hello Tom,

Is the TPN 1217B Power Supply out of a MSF5000 Base Station?

Dan

[Tom in D.C.]

Dan,

I don't know, but I just put up a Picasa site with a lot of photos of
the stuff/unit/equipment that uses this supply. It certainly looks as
if it's a base/repeater supply.

What they really need is a circuit diagram so they can dope out why
the output voltage is so relatively high. You can see the regulator
card in the photo set and it looks like one of the early ones with all
separate/discrete components, not the easy-to-fix three-terminal
type (Fairchild, etc.).

Regards,

[Dan562]

Hello Tom,

Now I remember this TPN1217B Motorola Power Supply, it did come out of a MSF5000 Base Station. It's a 250W Power Supply with Battery Revert and the kind Motorola Infrastructure Marketing I-D-I-O-T-S had the Power Supply and the RF Power Amplifiers R-E-M-O-V-E-D from the Service Manuals. Then the Field Personnel couldn't troubleshoot either unit down to component level at the customer sites. It forced most technical people to call the High Tech System Support Center for a FRU. These were the easiest units to troubleshoot in a shop or in the field.

Not to worry because Motorola Infrastructure Marketing Personnel have a terrible memory problem, like a dead short between their ears and the o-r-i-g-i-n-a-l Power Supply was a TPN1254A w/Battery Revert Option Included used in a Q2980A Series Digitac comparator. I just so happen to have that Power Supply copy. Let me get these pages photocopied and I'll send them out to your attention. Either PM me or I'll ship the Schematics out to your Ham Radio address.

Dan

[jackhackett]

I think you may be mistaken in believing that it's a 12 volt supply, it appears to be a ferro-resonant type, which I believe were spec'd at 15volts under load. The "regulator" board you see could be either for a low current supply, or more likely a trickle charger for the battery back-up, it sure isn't going to give you 250W with that one little unheatsinked TO220 transistor.

Of course I could be completely wrong.. in which case I plead that it's the weekend and I don't have access to any manuals, just my failing faculties

[Dan562]

Hello Jackhackett,

I didn't make the Motorola Marketing Specifications, these two Power Supplies listed below were specified in the Service Manuals although the 68P81092E80 for the UHF MSF5000 Base Station provided the wattage for the TPN1217B but no Schematics, PCB Overlays or Theory of operation.

The Digitac comparator Service Manual 68P06908B19-A under the Power Supply tab supplied the Model # TPN1254A, the wattage 250W, the Voltage +13.8 VDC, Theory, Schematics, PCB Overlays and you name it. And the only difference that I remember was the individual model number tags. All of the senior personnel that worked on these power supplies (including myself) are long gone from Motorola's Infrastructure Factory Depot when CTDI took over all repairs.

I left the Factory Depot in 1997 and worked for iDEN as a Field Engineer Implementing Nextel's Mobile Switching Offices around the United States and Canada and then transferred into the Digital Secure Product Group in Schaumburg covering many different Infrastructure Products and issues at the same time.

Dan

[jackhackett]

Interesting... looking through some manuals, I see they did the big power supplies a couple of different ways, some just use a capacitor on the transformer ferro-resonant winding, while some models use a regulator circuit driving an SCR across the winding, giving better regulation, and some degree of adjustability.

The manuals show the TPN 1271A as the former type, and specs it at 12.9V full load, 17.2V at 2A load. The 1217B might have added the SCR circuit, it's hard to tell from the photos. I don't see any adjustment pots in the the photos, as I would expect in a battery backup version (for adjusting the float voltage).

I'd be interested in hearing the final outcome here, good luck with it

[Tom in D.C.]

Jack,

Many thanks for your input. I've replied to Dan via PM about sending me
the diagrams. All of this information will certainly allow the club to get its
unit back into working condition. I'll post the outcome when I have one.

Regards,