I've started to restore a nice SR-150.? Never had one before.? I noticed the crystal for 3.5 is missing.? From the dust pattern it appears that the crystal was never installed.
Also, I noticed under relay K1 a very cool adjustment device on one of the relay contacts that has this contact making prior to the other contact with the use of a tiny adjustment pushpad?
on the relay swing arm.? Anyone know what is the magic going on here with these cascaded relay contacts?
The crystal for 3.5 should have been there as part of the stock radio. The only optional xtals were for the rest of the 10M segments with only one being provided as stock for 10M.
I am currently working sporadically on a pair of SR-150s and indeed see a adjuster on K1. Looks to be an adjustment of the armature itself. I would think this was from the Mfr as I cannot see Hallicrafters modifying the relays themselves. The set screw and nut have sealant applied to hold the setting. This is the only adjustment I see, nothing for individual contacts but then, I have not removed the relay cover to see the entire thing.
The relay looks like it may be the same one used in the HT-37 but it has been ages since I had that one open. My thought is I think this relay was a custom for Hallicrafters and the factory put this in to adjust the timing for xmit/rcv. When I built my HT-37 I had to buy the relay direct from Hallicrafters.
One of my radios is also missing the correct 3.5 xtal and has a close value one installed to make the radio play there but off for calibration. I will be looking for a replacement once I get past the issue I am working on now.
If I find out any more I will pass it along. Good luck. I am still hoping for the best with my two rigs.
73 ... Ed, WA9GQK
On Friday, December 20, 2024 at 03:26:49 PM CST, Dave Jordan via groups.io <wa3gin@...> wrote:
Hi Folks,
I've started to restore a nice SR-150.? Never had one before.? I noticed the crystal for 3.5 is missing.? From the dust pattern it appears that the crystal was never installed.
Also, I noticed under relay K1 a very cool adjustment device on one of the relay contacts that has this contact making prior to the other contact with the use of a tiny adjustment pushpad?
on the relay swing arm.? Anyone know what is the magic going on here with these cascaded relay contacts?
Dave Jordan