Galaxy 99v2 VR18 not responding

[MNTSIDE]

Hello
Have a friends 99v2 on the bench, was checking out the Tx tune and was noticing that, not only do I have to get the gate voltages way up to 4v or more,but wasn’t getting any response from vr18
This radio is very dirty on the scope also
If I back off on the gate voltages (like 3.5)
I get nothing for output
Any ideas what maybe causing this???

Thanks
Kevin

 

[Shadetree Mechanic]

Maybe possible that vr18 has failed?

 

[MNTSIDE]

Maybe possible that vr18 has failed?

Hey shade tree
Thanks for the response
I’m kinda new at this
Would you know how to check that vr18?

 

[groundwire]

Hey shade tree
Thanks for the response
I’m kinda new at this
Would you know how to check that vr18?

A vom

 

[Eldorado828]

Did you check the diodes under fets? Just a thought.

 

[MNTSIDE]

Thanx everyone
I have response now, but (this radio seems to be a mess
Trying to get a good sign wave on the scope seems to be a big hassle
Anything close to a clean wave, I have to turn the radio so far down it really dosnt put out much power
Can’t even get the 8-to 10 watts on high and barley 3 on the low side
And absalutly No swing to speak of

 

[Handy Andy]

VR18...lets' see...

Controls RF Power AM side, so that usually means they messed with Q56 and the support around it.

You're seeing 690010D on the silkscreen of the board right?

​

Use the Galaxy 98VHP to help with tuneup on that...

When you get into this, more than likely the Limiter has also been messed with you see that the "Boxcars and Squarewaves" will continue until the Flogging of the radio is complete...

Now the healing process has begun...

The issue around the Squarewaves though - did they keep the Amp board in there?

 

[MNTSIDE]

Thanks for that inf

VR18...lets' see...

Controls RF Power AM side, so that usually means they messed with Q56 and the support around it.

You're seeing 690010D on the silkscreen of the board right?

View attachment 58089​

Use the Galaxy 98VHP to help with tuneup on that...

When you get into this, more than likely the Limiter has also been messed with you see that the "Boxcars and Squarewaves" will continue until the Flogging of the radio is complete...

Now the healing process has begun...

The issue around the Squarewaves though - did they keep the Amp board in there

 

[MNTSIDE]

Thanks for that inf

Thanks for that vin Andy
Can ya tell me where the mod limiter is located , don’t really see anything clipped out

 

[Eldorado828]

Thanks for that vin Andy
Can ya tell me where the mod limiter is located , don’t really see anything clipped out

Q39 is the transistor the pull or clip, r264 is another they screw with and it's usually by adding a diode.

 

[MNTSIDE]

Thanks you guys for the info
So busy right now with work haven't had a chance to mess with it
ill keep ya posted on progress

Thanks again

 

[BJ radionut]

Andy's image just mag'd up a little