Hello!
I'm in need of some help with this piece of vintage electronics... as well as some translation issues.
I am by no means an electrician, but I am very interested in learning more about electronics. Fixing this piece of equipment could be an interesting project! Please go easy on me. ;)
(click the images to go to the full gallery)
Built in '72, this DP-5A Soviet Russian Geiger counter was working fine up until a few weeks ago, when I accidentally left it on (at the voltage calibration setting) and the batteries were drained. After replacing the batteries it was still dead silent when turned on - only the background lights worked. When I opened it up, I found this broken part in the probe, marked "47 MC". Of course, this is in Russian. A Cyrillic "C" is essentially pronounced like an "S". It appears to be a resistor (more below).
I'm using the three 1,5V cells from a stripped-apart European 4,5V battery to power the counter instead of the original soviet-design 1,5V cells that are no longer easily found (for obvious reasons). For all I know the soviet cells may have had some built-in feature to prevent this damage, but It still seems strange that it would break simply due to drained battery cells, so there may be other things going on... However, this resistor is the only obvious damage I could see, opening it up for the first time, and it's the only thing I know is wrong with it right now.
Here's the second resistor of the same type, seemingly intact:
Looking at the documentation, the broken resistor seems to be marked number 7 and the intact one number 8:
Here's the list of parts with number 7 and 8 listed as "Pe?????? ???-0,125-47 ??? +/- 10%" (sorry, Cyrillic script dosn't seem to be supported by these forums):
Loosely translated it seems to mean "Resistor KIM (or KEM)-0,125-47M Ohm ± 10%". If this was a normal resistor I should be able to find some replacements in my collection... But I'm not sure it is. All the other resistors listed - the red ones that actually look like your average, if mostly unmarked, resistor - have another prefix: "???" (MLT).
And what is actually the specifications of these two? "-0,125-47M Ohm" it says. Is the first one some sort of amperage or voltage limit? Would the second value then be the resistance? My multimeter isn't helping either - it is not detecting any connection at all between the two ends of the seemingly intact resistor most of the time and the few times it does it jumps around the 20M Ohm range. I figure this could be due to coating on the wire and solder points... Then again, reading on the leads on the sides works just fine. Maby this second one is broken too? Must I remove it before accurately measuring?
And that is the issue.
TL;DR: What are those two resistors and what could I replace them with? Please share any ideas/info you have!
External pictures and general info on the counter can be found here (the B variant is very similar to the A):
http://boginjr.com/electronics/old/dp-5b/Russian alphabet:
http://en.wikipedia.org/wiki/Russian_alphabet#AlphabetI figured I may as well document the rest of it for people interested in it. You can find a bunch more pictures of both the unit and the documents related to it in the album here:
http://imgur.com/a/4tYBYWhy did I post here of all places? Well, most of the forums I found regarding vintage electronics were either very inactive, completely focused on radio or audio or didn't take help requests. If you have any tips of forums that may be of help; do share! :)
Thanks for reading. I will of course keep you updated if any progress is made!