MRF477 deceased, leaves behind grieving owner of Galaxy DX66V.

[Cable Guy]

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.

 

[SuperLid]

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.

 

[Cable Guy]

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.

 

[SuperLid]

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.

 

[SuperLid]

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.

 

[Lkaskel]

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!!!!!