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F-2806 One down three to go.

avionic

avionic

" Black Knights " F-15 back shop EW avionics
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F-2806 One down , three to go.

Doin a little rebuilding - New caps ( silmic II's and Nichicon PW's),Bourne multiturn trim pots,New fusible resistors (KOA Speer 1% Metal film/oxides) New diodes and new transistors where needed.
 

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That looks better :thmbsp: - did you chose 100v, 470uF to fill the clips better? - I expect 80v, 470uf would have rattled around a bit.

So, we know you have a couple of G-8000 and/or G-9000 - care to share a smidgeon more of this project... :smoke:
 
Actually its only one G-8000 with a spare set of driver boards.
 
80 volt caps are not commonly available. 100v is the common substitution.

- Pete
 
Well that's what I found too - being in the UK, however I found 80v are a LOT more commonly available via US based suppliers.
 
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Just an FYI. The multiturn trimpots are handy for the bias adjust on these boards, but not on the offset. For the offset, single-turn pots are much handier, since both need to start out close to the center of their range and adjustment entails a coarse adjustment and then a fine adjustment. With multiturn pots on the offset, you have no visual frame of reference for the center of the trimpot range.

Then there's the little ceramic cap that sits right where the adjustment screw is for the offset if you use a multiturn pot. I move this cap to the back side of the board to clear the way.
 
I've already relocated the little ceramic caps.As far as the multiturn offset trimmers go.I'm very used to counting turns.When aligning video processors on electronic warfare (ECM) systems.SOP was to center the trimmers travel.On these bourn trimmers "25 turn",once you reach the "end-of-travel" they "click".Then you just count 12.5 turns in the opposite rotation to get in the ballpark.Easy for me! Now maybe the next guy will be cussing me out.:D Before installing these 100 ohm trimmers I had centered them using a DMM.
 
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avionic said:
Doin a little rebuilding - New caps ( silmic II's and Nichicon PW's),Bourne multiturn trim pots,New fusible resistors (KOA Speer 1% Metal film/oxides) New diodes and new transistors where needed.
Click to expand...

You rebuilt a lot more than I did :D. I only changed out the R17 and R20 150 ohms. Do you recall which 470 uf Nichicon cap that is. Mine were not a good fit diameter-wise for the clamp. I used electrical tape around the cap to make up the difference. It works but sure looks like crap. I believe they are PW series.
 
geode said:
You rebuilt a lot more than I did :D. I only changed out the R17 and R20 150 ohms. Do you recall which 470 uf Nichicon cap that is. Mine were not a good fit diameter-wise for the clamp. I used electrical tape around the cap to make up the difference. It works but sure looks like crap. I believe they are PW series.
Click to expand...

Neither were these..Nichicon PW's.. Black Permatex -a little dab'l do ya..
http://www.permatex.com/products/Au...ermatex_Black_Silicone_Adhesive_Sealant_b.htm
 
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Well got three of the four dialed in..One still has a problem " Keeps the amp in protect"..Haven't really had time to T-shoot it yet..Thinking maybe I didn't get it plugged in correctly to the G8000-- very easy to get it plugged in 1 pin off..Grrr..
 
It is easy to get it one pin off. Check the resistors between the heat sink and the connector. A 56 ohm and a 47 ohm are probably toast.

- Pete
 
LBPete said:
It is easy to get it one pin off. Check the resistors between the heat sink and the connector. A 56 ohm and a 47 ohm are probably toast.

- Pete
Click to expand...

Good thing I picked up plenty of spares of everything..I now use a small inspection mirror and bright light for inserting these..Adapt and overcome..:D

Update: 4th board had a overlooked cracked solder connection on the 2-pin input connector.
 
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Dear Avionic,

I am looking for Couple of Driver boards for G-8000 please let me know where i could find it.
Earlier there where some other missing boards as well but i finally found them last week.

Re,
PRASHANT
 
avionic said:
There usually attached to a G-8000.
Click to expand...

:D Our friend Prashant has a G-8000 where these have been removed and lost, the unit also sports extensive butchery and non-standard additions. :sigh:

Prashant - I think you might have to buy another G-8000 to obtain all the parts you need, or do some smart work buying the individual parts from a unit being parted out. If you buy a whole unit, after reconstructing one G-8000, you can then sell the remaining parts to recoup some of your losses.
 
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Dear Avionic,

Is it possible for you take high resolution pics and/or scan copy of the track-side and component-side of the PCB F2806.

I have a technician here who can resurrect F-2806.

Thanks in advance.

Prashant
 
I can understand why high res pics of component side would be handy if attempting a rebuild, (actual components used checked against the service manual) but I think it might be a bit of a big ask for someone to strip a g8000 to get a few track side pics.

you could, if pushed get the service manual from:
http://www.hifiengine.com/library/sansui/g-8000.shtml

and using clear acetate sheet and a sharpie, pen over where the copper is and then do the process of applying resist to a copper pcb board, apply UV remove acetate sheet, etch with ferric chloride, clean off resist and drill, possibly painting a protective coat over the bare copper.

I did do this once, actually got descent results of the copper tracks on a pcb, I just never drilled and finished. But it is do-able

Bit of a job, goodluck
 
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