2970 needs to warm up??

[Harley3315]

Not so much a mod but an issue wasn't sure where this topic belongs. So I've got a second gen of the original 2970s the one with out the battery for cpu memory uses a cap instead. When plugged in turned on it will not receive or transmit for about 10 mins at room temperature for days doesn't matter power it up it indicates TX on the screen sounds like its going in to TX but it's not 10 mins power on presto works like a champ. I've checked the 2 8 volt regulators on the side and the 5 volt on the front of the board all voltages check fine. Any ideas? Thanks in advance.

 

[9C1Driver]

Cold solder joint.

 

[Harley3315]

I'm thinking more along the lines of bad caps there are a few places there are 10 volt caps in there I'm thinking at the very least change those.

 

[711]

VCO area

 

[Harley3315]

Your saying caps in that are or cold solder?

 

[711]

Common problem for older 2950, can’t recall the cap but it’s a value change in the pF range

 

[midnight special]

hmmm i have a galaxy 2527dx it is just like a 2950 only in the big black box style,,,it is 5 kc off when i first turn it on but after warm up of about 10 minutes it works perfect,, i wonder if i am having same issue,,,,,

 

[Harley3315]

hmmm i have a galaxy 2527dx it is just like a 2950 only in the big black box style,,,it is 5 kc off when i first turn it on but after warm up of about 10 minutes it works perfect,, i wonder if i am having same issue,,,,,

You indeed could have a cap that's weak yes after it warms up it drifts on to center

 

[newoldguy]

i have had problems with cold solder joints int the 2950 board usually at the regulators a few times the regulator itself was bad. the 2527 problem i would try to heat the solder joints at the vco and around the mixer crystal cold solder joints can really be a pain to trace them down but those areas are where i would start first