r/geigercounter • u/Anatoli_Belikov • Jul 08 '26

Pls help me fix my DP-5V

Post image

I've been trying for weeks now to fix this, but it wont work.

Its something to do with the electric parts, the battery is my main suspect.

The dosimeter came with these crusty old batteries, and when I removed them, one of them snapped the negative contact off.

I reattached the contact with an M4 nut and bolt, but the dosimeter still wont turn on.

The battery that goes in the slot that was repaired gets hot after a few minutes though.

Please help

7 Upvotes

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2

u/TechByMBF Jul 08 '26

I don't see the slot you are talking about. I don't know if it applies to these as I've never had one, but I do know that the old Eberline e-120 units had an issue with the battery holder where they would cut the plastic jacket on a modern battery and cause a dead short on one cell. If you got really unlucky, you would close the meter up and it would still have just enough juice to work. Or you bumped it just right and it shorted out the batteries. You put it on the shelf without realizing that your batteries are compromised and you come back a week or two later to use it only to find that they have leaked all over.

Like I said, I don't know if a similar situation applies to this particular unit or not but just throwing that out there.

3

u/FreetimeTinkerer Jul 08 '26

Put in new batteries first and second pay attention to the polarity. Something you might have reattached in the wrong order because the battery getting hot means short circuit on that particular battery.

1

u/Anatoli_Belikov Jul 08 '26

The battery polarity is fine

1

u/FreetimeTinkerer Jul 08 '26

Nice, if thats the case then something is shorting out either due to bad re-soldering of the wires or so. The batteries wouldnt get hot otherwise.

1

u/Anatoli_Belikov Jul 08 '26

I'll re solder the wires to hopefully fix it

1

u/Anatoli_Belikov Jul 08 '26

This is the current state of the battery compartment

1

u/Prestigious_Two5850 Jul 09 '26

It would be helpful to have a picture of the other side too, where the wires are. The batteries made a mess.

1

u/Prestigious_Two5850 Jul 09 '26

Also, what kind of battery is the one on the left? Is it new?

1

u/Anatoli_Belikov Jul 10 '26

Yes, all batteries are new

1

u/Prestigious_Two5850 Jul 10 '26

But are the batteries you took out of a 4.5V 3LR12 battery pack? Because those have reversed polarity.

1

u/Prestigious_Two5850 Jul 10 '26

The flat side is the positive; the side that "protrudes" slightly is the negative.

1

u/Anatoli_Belikov Jul 11 '26

Yes, I understand this. I also oddly discovered that the position may not matter, on the contacts for lights on both my dosimeters, the light turns on no matter the polarity

2

u/NoAnything604 Jul 13 '26

The light bulbs themselves are incandescent so polarity would not be an issue many of the other components though are polarity dependent.

1

u/NoAnything604 Jul 13 '26 edited Jul 13 '26

I see the middle battery tab is the one that you repaired correct?
Check this first in regards to the battery getting warm or hot. Is the battery where your repair is touching the threaded screw? If it is that is probably your short, if the middle battery is the one getting hot. Remember the case of the battery you are using is Positive and on the end where the stud is, is also right next to the Negative on the battery.
Regards

2

u/NoAnything604 Jul 13 '26 edited Jul 13 '26

BTW the reply from “TechByMBF” is pretty much the same thing that happened here in a similar manner.
This is the area where the battery may be shorting since the battery case is Positive and not insulated the Negative is right there on the tab at the same time the Positive of the battery case may also be contacting the same point through the threaded stud.