Discussion in 'Amateur Radio Amplifiers' started by WA6MHZ, Jul 31, 2017.
Time to get back to work!!!
Keep us posted.
Today we installed the smaller coax we got from SUE, a piece of what? RG-142 or something like that. It has a nice double shielded braid on it but is the size of RG-58. it supposed to handle QRO Power!!!
After church, I removed the existing RG-8 coax and stripped back the cover on the new coax.
Then it was soldered in place
and at the RELAY
Sue didn't like the piece of 18 gauge wire I used for the NC to NC jumper so that was replaced with some solderwick (inside the heatshrink tubing)
So it was time to plug it in
TO my great joy, there was no BLAMO!!!!!!
Grounded the relay key point and the relays keyed as they should.
I then powered it down, turned the amp upside down and adjust the bias current for 125mA.
Then it was tried out on all bands, and everything was wonderful!!!
LOTS AND LOTS of power!!!
I called up the owner and gave him the joyous news!!!
but then, mid call, I noticed something
The plate meter read 125mA while the amp was in RECEIVE!!!!!!!!!!!!!
I called up Sue and she thought it might be the FET Q6.
luckily I had one spare
I went over the W7RY QSK board extensively and could find Nothing wrong!!
the FET was replaced and it did the same thing!!!!!!!!!!!!!!!
Then I remembered the sillyass little ZENER SUB board STILL INSTALLED above in the diode board
I tore that out and tried again!!! THEY Don't mention in the Docs that the Zener or diode board needs to be removed. But tearing it out did the trick!!!
Now it worked perfectly and the plate idling current was reset to 125mA
Everything was just rosy, so I put the case on and tried it on all bands. WELL over 1KW OUT (wattmeter only goes to 1KW) in fact the meter pins on the SSB MODE!!!
On 10 meters we get 700W out. that will hafta do.
So it is now officially FINISHED and ready for Service!!!
This is a SUPER SB-220 now!!!
before I hear squawks about this picture
it looks like the braid is too close to the flat metal strip and the relay coil contacts. THIS was CORRECTED after the pic was taken!!! NO PROBLEM NOW!!
Looks Great Pat!
Now I need ANOTHER SB-220 to play with!
Took the SB-200 to the HRO Swapmeet, lots of people looked at it, but no one gave any offers or got out their wallet.
Yesterday took it to HRO and put it on the consignment table with a price tag of $400 and it SOLD within TEN MINUTES!!!!
Then, before Beer last night, the good Nun and I went back to HRO to get some more red and black wire for the project and WOW!!! there was ANOTHER SB-200 on the consignment table!!! It was highly Modded and had one wrong KNOB on it and he wanted $400 too!!! Think that one will sit there for awhile!!
Had someone thrown down $300 on the table at the Swapmeet, they probably would have taken it home!!
So I am just delirous at $400!!! Maybe I shoulda asked $500!!!
Pat someone once told me there was an ass for every seat.
Just when I was TICKLED that Amp sold so fast, I got a message from the store that the buyer had returned it very disastified. WTF???? I rushed up to HRO and picked it up, and brought it back to the Radio Hospital. I was most dismayed he had only put in about 4 of the top screws to hold the lid on, so I got ripped off for a dozen screws!!
He has sent photos claiming it was DUSTY inside. Well, I had tried to clean it before the sale, but guess the dust moved around abit.
He claimed it was ARCING AND SPARKING inside with 20 Watts of drive. I saw no arcing after much flexing of it. I then made a YOU TUBE video of the testing of it. It works great. So the problem is on HIS END!!!!
So if he doesn't want it, I will find someone ELSE who does!!!