Finally got around to replacing the old corroded soldered-in D cell in the RCA Voltohmyst with a new battery today.
Snipped the wires off the battery and into the trash it went. Had to drill out a rivet to remove the battery holder clip.
The battery holder is a little on the big side and just fits into the space vacated by the old battery and clip. Soldered the wires onto the battery holder and fastened it to the Voltohmyst using some double sided tape.
Now it’s got a new battery that can be replaced whenever it’s needed.
Next thing to do is go through the manual and read up on how to calibrate the meter.
No smoke, popping or other unusual sounds/odours when I plugged it in. Some initial testing with batteries and some resistors suggests a bit of recalibration or maybe a bit of repair might be needed though.
Removing four screws from the back lets you take the back cover off (a fairly substantial chunk of cast aluminum) revealing the innards of the meter.
The blue adjustment screws are trim pots used for adjusting the meter calibration.
One thing that surprised me was the presence of a soldered in D cell.
No idea what vintage the battery is or what it’s used for (at the moment), but my multi-meter showed it still had 1.4 V across it. The battery has definitely seen better days. I think I’ll see about replacing the battery with a battery holder so it can be removed and replaced in the future. Fortunately it looks like the wires have enough slack to work with.
The rest of the meter looks to be in pretty decent shape, and pretty clean. Without taking off the face of the meter, it’s a little hard to get in there to check out the middle. There are two tubes in the unit, a 12AU7 and 6AL5.
Lots of colourful wires at the range selector and mode selector switches.
The probe for the meter is a big chunky thing, about the size of a Sharpie marker.
Next step will be to go through the manual and read a bit more about the meter works before I try to dive in and replace things.
One of my friends from the photography meetup I’m in messaged me and asked if I’d be interested in an old radio he was helping a friend of his sell.
I’m now the owner of a Hammarlund HQ-100 receiver that powers on, but will need a fair bit of restoration work.
I even got a speaker to go with it.
It’s a bit of a heavy beast, but not quite as heavy as it looks. Undoing two screws let me slide the cover off to look inside.
There’s a fair bit of dust and corrosion on the components, but except for the band spread dial, all the controls seem to work. Not sure how the radio spent the last few decades of its life. I’m pretty sure I’ll have to replace a few components, especially the mechanical bits. Smells like the previous owner might have been a smoker, but it’s hard to really tell.
This is going to be a fun restoration project to work on. It’s going to take me a while, but I’m going to enjoy working on it.