My new or old SG85/URM25D

Discussion in 'Technical' started by W6MQI, Dec 30, 2017.

  1. W6MQI

    W6MQI Member

    Picked up a SG85/URM25D for $40.00 these generators aren't super duper HP's, but they work. This unit didn't work there was no output on X-Mult port. output was intermittent on X200K port, and the meter didn't function in %MOD mode, neither 400Hz or 1000Hz position. I first recapped what I could easily get to, cleaned all switches, BNC connectors etc. Intermittent output on X200K port turned out to be a burnt R129 resistor that was an easy fix. No output on X-Mult port turned out to be a burn up attenuator BUMMER:twisted: not easy to fix some dork must have put B+ on the X-Mult port without a blocking cap, I assume the same thing happened with the X200K port. Luckily I found another parts unit on Ebay for a $1 plus shipping. The attenuator in this unit was in working order so I swapped out the toasted unit with the new one now the X-Mult port was working again. Found two open Geranium diodes replacing those fixed the non functioning meter in %MOD. Also replaced the tuning knob, and vernier scale which the original one didn't have. So far its been working just fine seems real stable, and the dial is accurate surprisingly. Its easy the dial up say 7.000Mhz, but anything finer then that it becomes hard to move the dial smoothly enough to really get it tits on frequency. For what I'll be using it for a reading of 7.000Mhz is close enough no need for 7.000000Mhz.

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