Help with Yaesu Quadra amplifier

[W4AJF]

Hi all, hope someone out there has familiarity with the Yaesu Quadra and can help a friend of mine overseas. 2 problems:

a) LOUD buzzing sound on transmit from VP-1000. Can not be heard by person who is being spoken to, only by user. Buzzing increase with output.
b) When tuner is engaged, receiver is attenuated like 20db and error message comes up: 1002 / SWR 1: 3

All testing done either in to a dummy load or an antenna with 1.3:1 SWR.

Hope someone can help (please??).

Thanks,

Adam Farber W4AJF
Cooper City, FL
adamf@eeco.com

[k9yli]

well at least for the buzzing sound and it increases with power output maybe.
Sounds like transformer talkback.
Try tightening all screws around the transfomer. especially the ones that
hold the laminations together or the coil cover if its a covered transformer.

Also a trick is get a dowel stick or wooden shishkebab stick, chop stick etc.

put it on the chassis near the transformer and up to you jaw bone by your ear.
see if it seems to be mechanical vibration. or right on the transformer frame..

if its talkback its caused by loose windings on the transformer.
maybe pouring some varnish into the windings and letting dry will firm them up.
loose screws mounting transformer to chassis can also cause the vibrations..

[W4AJF]

Hi, thanks for trying to help. Actually, there are no screws around the transformer, it's soldered in so that won't work but I appreciate the post.

Still looking for help if anyone is familiar with the Quadra.

Thanks,

Adam Farber W4AJF
Cooper City, FL

[k9yli]

It still may be caused by the transformer. use the stick method or a stethoscope if you can get one to see if its mechanical vibration..

then it maybe you would have to replace the transformer.

[S53MM]

Hello guys

I think I have the same probleme here with buzzing sound on SSB or clicking like relay on CW at every dit/dot. My Quadra was bought in 2008.
The problem is indeed in big L7 coil. I ordered new coil at yaesu and replace it in the VP-1000. Same story.

So I opened this L7 coil, which's core is actualy from very thin iron leaves. Outer part (shelter)is from some insulator, not ferrite material.
The very outer (and) inner part of this iron leaves were somewhere not sticked to the next layer so when moving it with knife it it produced the same sound that is bothering me.
Next step was that I put this whole iron core to new polyesther pitch, which unfortunately didn't bring any improvement.
I belive there is some space inside the core between the iron leaves. It must be a whole bad series of these coils manufactured in last years, because the new coil i have ordered acted exactly the same.

I think the solution is to put in whole different coil from some other manufacturer.

Any other news on this subject?

Matija/S53MM