Question about G07 repair kit.

[Witchboard]

If a bad flyback usually takes out the horizontal output transistor, why isn't it included in the repair kit?

[Ken Layton]

In my experience a bad Electrohome monitor flyback only takes out the horizontal output transistor maybe 25% of the time. The last couple dozen Electrohomes I've done that had bad flybacks surprisingly did not take out the horiz output transistor. That's probably why the transistor is not included in the kit.

[Witchboard]

Ah, okay.  I have a G07 with a bad transistor.  Is that pretty much a sign that the flyback is toast?

[Ken Layton]

Yes, that's a pretty good indicator of a bad flyback. Original flybacks are failing all the time. An original has a paper label with "A29951-B" printed in a green band at the top of the label.

[Witchboard]

Thanks Ken.

[Witchboard]

Hey Ken, do you know a good source for these transistors?

[Ken Layton]

Mouser doesn't usually stock the Japanese "2S" series of transitors. They concentrate mainly on the US standard "2N" series.

MCM Electronics (www.mcminone.com) has the 2SD870 for a decent price. It crosses to NTE 89 also. You can use a 2SD871 as a sub, too.

[Witchboard]

Very cool.

[Ken Layton]

Yes, use the standard G07 capkit for the CAO also. Go to Bob Roberts' site (www.dameon.net/BBBB/) and read about what caps you actually use out of the standard kit when doing the CAO.

[Witchboard]

Thanks Ken.  Will do.

[Witchboard]

Bah.. just shoot me and get me out of my mysery.  I was looking over my CAO and I have a cracked peaking coil (A75360-6).  I haven't been able to find the part nor a cross reference.  I've tried Jameco, Mouser and MCMinone.  I've found plenty of places that carry peaking coils, but I don't know the specs of the one I got. 

[Ken Layton]

If you carefully unsolder it you can patch it with silicone glue and be able to reuse it. Once you unsolder it check continuity of it with an ohmmeter.

[Witchboard]

Okay, I'll give it a shot.  Thanks again Ken.

[Witchboard]

I repaired the coil and it's working.  Yay.    I have one last question on this kit with the CAO. 

The C-511 location on the CBO cap map calls for a 47uF 160V, but the CAO has a 100uF 160V axial cap at C-511.  Bob's CAO instructions say that I'll have 3 left over caps, but the 47uF 160V cap is not one of them.  Do I replace it with the included cap or leave well enough alone?  I'm ordering a custom kit from Zanen, should I just order a 100uF 160V axial cap to play it safe?

[Ken Layton]

You should double check the schematic for the CAO to see if someone had replaced that cap before and used a 100 uf instead. I don't have a CAO schematic, but if that cap is indeed a 100 uf that's in there now and it's never been replaced than you should probably get a 100 uf. The 47 uf would probably work though, but to play it safe order the 100 uf.

[Witchboard]

I don't have a schematic for the CAO either.

[Ken Layton]

No this larger (electrically) capacitor probably would not have damaged anything. Unless of course the caps leads touched an adjacent components leads.

[Witchboard]

The leads were insulated, so I don't think that's an issue.  Thanks again Ken.