[GarySP]

Hello everyone. Picked up a Triplett Professional All Wave Radio Servicer model 1175b this weekend. The unit was built for the National Radio Institute around 1941. It's in visually good condition, but I haven't gotten into the guts of it yet. It contains a 4 band rf signal generator covering 130 kc to 28 mc, and a 1000 ohms per volt ac and 5000 ohms per volt dc multimeter. I had heard that Triplett made very good instruments, and I could use both of these instruments since I don't have a signal generator or a 'period correct' VOM as of yet. I was able to get a complete reference manual and schematic from the "other" forum. It was battery operated, so the first thing would be building a power supply for it. It has two 30 triode tubes inside, so if it is a bust the tubes are probably worth more than the $5.00 I spent to get the whole thing. Thanks in advance for any input. Take care, Gary

[klondike98]

I would think its worth rebuilding especially since you have all the documentation. If successful you have a nice period diagnostic and alignment tool, if not you've only lost a few bucks and some time.

[morzh]

To me any previous era diag tool is worth rebuilding as first you could use it and then it's just nice to have it work.
I have my HP200 oscillator and it works great, and it is usable.

[codefox1]

If you have time, I'd give it a try. At least you wouldn't have to interpolate when using said instrument on period specimens. It's worth it to you.

[TA Forbes]

Yes, Triplett instruments were pretty good. Often when working on old radios and equipment the 1000 ohms/volt and 5000 ohms/volt are required.

The problem with restoring an older sig gen is verifying frequency, wave-form amplitude, and waveform "cleanliness," or lack of distortion.

Even with a calibrated sig gen, it is a good idea to verify output frequency and if necessary amplitude with external test equipment when doing an alignment or other tasks...

[codefox1]

Very inexpensive modern digital frequency meters as well as cheap surplus ones can be had online. I use one to fine tune my ancient generator after warmup of 10 minutes.

[brownie45]

How about a scope to look at the waveform/ freq?
Use that to verify?

[tom.seeger]

Well everything is worth rebuilding if you enjoy it. However if you are looking to make a buck or two selling it, forget it, its not worth s#*t.
I love the challenge. But that's just me.

[Arran]

Actually you may be wrong there, there may be some appeal with the fact that this unit was supplied with a NRI radio course, and Triplett test equipment was usually of good quality. Test equipment from a correspondence course, especially early equipment, is not that common, not like Heath, Kinight, and EICO kit stuff. It's sort of like Philco branded test equipment, although Philco did not manufacture test equipment it is somewhat collectable because it says Philco on it.
Regards
Arran

[GarySP]

Hello all. Opened the unit up today and found it to be in fairly good condition, all things considered. It didn't have batteries in it, but a few notes written way back when about the instrument that is making me reconsider rebuilding it. The one note that has me considering my options was "signal generator operates erratically". The unit operates with A, B, and C batteries, 1.5 volt, 4.5 volt, and 45 volt respectively. The 1.5 and 4.5 were simply D cells. The 45 volt was an old burgess radio battery. Figure I can put together five 9 volt batteries to make up that if I chose to go further with it. Several caps to replace and resistors to check at this point. We'll see...... Take care, Gary

[Paul Philco322]

When my Dad worked for the Edison they still used D cells from Burgess, I guess they hung on a while as that was the 60's. I know some people who collect old radio battery cartons and such, interesting and some good logos. Good luck with it Gary.

Paul

[GarySP]

OK everyone, ran into another curve with this unit. What can anyone tell me about copper oxide rectifiers? Seems this unit has one on the VOM section, I'm presuming to rectify AC voltage before the meter. It also has what looks like a variable resistor which I would think is for calibration purposes? The whole thing is built into a standard 4 pin tube base. How would I go about testing this unit? If bad, could I rebuild it using selenium diodes? Learning as I go... Take care, Gary

[GarySP]

Hit a new curve with this unit. What can anyone tell me about copper oxide rectifiers? There is one of these in the VOM section. I'm presuming to rectify AC voltage before the meter. It has a variable resistor inside labeled 233 ohms. Would this be for calibration purposes? How do I test this unit? If bad, can diodes be used to rebuild it? The whole assembly is built into a standard 4 pin tube base. Any info is appreciated. Unfortunately, the paperwork I got only cover usage instructions and a schematic. No information on how to calibrate it. Take care, Gary