What's a MRF-475 Worth?

[HomerBB]

I can get 5 of these, and maybe as many MRF-497s.
He has the 495s, and has yet to locate the 497s if he hasn't lost them in time.
Any idea what they are worth?

 

[AudioShockwav]

I think they used the MRF 475 in some of the old Drake radios.
You can still get NOS for about $10 bucks each.
MRF 497 is a drop in replacement for the MRF 477 used in the HR2510/2600/Lincoln/Jackson type radios and cost about $40 to $50 bucks each new, but they are in VERY limited supply.


If he has the 497 I would grab them.......... If the price is right.


http://www.rfparts.com/transistors_MRF-TP.html

Scroll down to the part number/prices

73
Jeff

 

[HomerBB]

I'm hoping he locates them in his stuff somewhere.

The price should be right.

 

[IMD262]

I think they used the MRF 475 in some of the old Drake radios.
You can still get NOS for about $10 bucks each.
MRF 497 is a drop in replacement for the MRF 477 used in the HR2510/2600/Lincoln/Jackson type radios and cost about $40 to $50 bucks each new, but they are in VERY limited supply.
Appox 40 watts@ 12 volt.

If he has the 497 I would grab them.......... If the price is right.


MRF - SRF -TP Transistors at RF Parts Company

Scroll down to the part number/prices

73
Jeff

Don't you have to "cross the legs" of the 497 to use as a replacement for a 477?

 

[ExitThirteen]

IMD262,

Nope, you don't have to "cross the legs" of the MRF497 to use in place of an MRF477. The MRF497 is a 60W transistor, the MRF477 is a 40W transistor. However, the MRF477 has higher gain (about 15), where the MRF497 has lower gain (about 10). That being said, they have similar output when used in the 2510/2600 radios. The MRF497 is a direct drop-in in this case.

If a person were to install one of these into a CB radio, THEN you'd have to "cross the legs" on the MRF477/497 to make it work, along with doing other changes to the final section of the radio.


~Cheers~

 

[AudioShockwav]

Exit 13 nailed that one, 100% correct.
You will not usually see a power increase with the 497 because it has lower gain.

RF parts Limits the sale of this transistor to a Max of 2 per customer because the supply is so limited...... I think Durham radio might have a few left as well, but other than that....the supply is about dried up.
You can find a few here and there at older radio shop`s that have a few NOS in there parts bin, but that is about it, and like many of the no longer made transistors you can find useless fakes from Honk Kong on E Bay

I think Weazle88 on EBay has a Sub now custom made by Eleflow that is also a direct replacement for the Motorola 477, it is to be had for Approx $30 US plus shipping from the UK ( approx $12 US) He is the ONLY person I would trust there to buy a replacement from, the Motorola parts are about as pricey as it gets.
73
Jeff

 

[mr_fx]

however is you rework the predriver section you WILL see a increase with the 497

not only that but it has a lot of headroom to work with

 

[AudioShockwav]

IMO it is not worth it.
This Radio was designed to be a 10 watt AM/FM and 25 watt SSB radio, Why take a great radio that is no longer built and Add additional stress/heat to it for a small amount of gain?
You need more power, buy an amp, do not hack a great radio.
Not my idea of a good move at all.
73
Jeff

 

[IMD262]

Any of you guys ever use a 2sc1945 in place of a MRF-477? I have a 6 band Jackson with a bad final.

http://www.eleflow.com/2SC1945.pdf

 

[AudioShockwav]

STEP BY STEP MRF477 TO 2SC1945 LINCOLN REPAIR - YouTube

Replacing the MRF477 with a 2SC1945 in a President LINCOLN.
As long as the output circuit of the transceiver has no other faults results are good and since making my other video this has been tried in many radios with varied results, as much as 22 watts PEP has been achieved from a JACKSON although it is wise to keep power down to 16 watts for a good service life.
Bias current adjustment procedure = http://www.cbtricks.com/radios/uniden/hr_2510/hr2510_tx_adj.htm -

73
Jeff