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MRF477 deceased, leaves behind grieving owner of Galaxy DX66V.

Cable Guy

Packaged by weight, some settling may occur.
Dec 29, 2010
415
349
73
West Tennessee
It worked well for many years, until it didn't. Schematic says the 66v had a 1969 in it. It has a hard wired bias with no control (no VR). Is anyone familiar with the 477 upgrade to this chassis? If so, is it probable that bias values and/or input/output networks were tweaked to accommodate the 477?

I haven't looked too hard at it yet or compared it to schematic. I'm thinking of putting it stock, as the $$$477 is in the $$$clouds, using either a working Motorola 1969 pull or a new eleflow 1969 (CB20). Any changes I might need to watch out for before I get started?

Thanks always.
 

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It worked well for many years, until it didn't. Schematic says the 66v had a 1969 in it. It has a hard wired bias with no control (no VR). Is anyone familiar with the 477 upgrade to this chassis? If so, is it probable that bias values and/or input/output networks were tweaked to accommodate the 477?

I haven't looked too hard at it yet or compared it to schematic. I'm thinking of putting it stock, as the $$$477 is in the $$$clouds, using either a working Motorola 1969 pull or a new eleflow 1969 (CB20). Any changes I might need to watch out for before I get started?

Thanks always.
I have replaced the MRF477 with the 1969, CB20, IRF520, IRF530 and IRFZ24. If you need CB20, I have them. The best so far, is the IRFZ24, but you have to do some circuit changes and is a bit of work. I can't recall which I have i my MK1 Jackson. Either a 520 or 24.
 
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Thanks SuperLid, I bought a stash of cb20s' a few years back and they are adequate. I've also just received a tube of vishay 520s from digi but I know I don't have what I need to convert it to MOSFET. I think all I'm missing is an assortment of npo caps, I have assortments of everything else I think.

I've given myself this day to look over this radio and I wasnt sure the 477 would bias the same as stock 1969 or have nearly the same in/out impedance, but ill double check the values as i go.
 
Thanks SuperLid, I bought a stash of cb20s' a few years back and they are adequate. I've also just received a tube of vishay 520s from digi but I know I don't have what I need to convert it to MOSFET. I think all I'm missing is an assortment of npo caps, I have assortments of everything else I think.

I've given myself this day to look over this radio and I wasnt sure the 477 would bias the same as stock 1969 or have nearly the same in/out impedance, but ill double check the values as i go.
The MOSFET does not bias the same and you will need to convert. They do work.... I saw 24W or so PEP w/ the 520 and around 30 or 34W PEP with the Z24, I can't remember the exact numbers There is bias drift with heat and I do see output change when it heats up, but they do work. Beats the hell out of sourcing and paying for the MRF477.
 
Thanks SuperLid, I bought a stash of cb20s' a few years back and they are adequate. I've also just received a tube of vishay 520s from digi but I know I don't have what I need to convert it to MOSFET. I think all I'm missing is an assortment of npo caps, I have assortments of everything else I think.

I've given myself this day to look over this radio and I wasnt sure the 477 would bias the same as stock 1969 or have nearly the same in/out impedance, but ill double check the values as i go.
I should have mentioned, I tested the HG MRF477...it sucks, don't waste your time and money.
 
It worked well for many years, until it didn't. Schematic says the 66v had a 1969 in it. It has a hard wired bias with no control (no VR). Is anyone familiar with the 477 upgrade to this chassis? If so, is it probable that bias values and/or input/output networks were tweaked to accommodate the 477?

I haven't looked too hard at it yet or compared it to schematic. I'm thinking of putting it stock, as the $$$477 is in the $$$clouds, using either a working Motorola 1969 pull or a new eleflow 1969 (CB20). Any changes I might need to watch out for before I get started?

Thanks always.
I must say, you have the best title for a tread in a long time!!!!!
 

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