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Squire 100 "Bi Linear" "Amateur Amplifier"??

LeapFrog

Wielding Hanlon's Razor
Feb 15, 2016
1,709
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Anchorage, Alaska
Before I "get the talk" please let me say I know it's Grade A+ Junk, but I can learn something here.

If anyone can help me identify this amplifier I would very thankful.
I specifically need to know what transistor came with this fm/cw amplifier back in the day?
"The Squire 100
Electronics Unlimited
Lebanon, Tennessee"
[photo="medium"]4398[/photo] ..
70's Made no doubt.
Notice the serial on the "FCC Sticker" matches a series of digits scratched/etched /drawn on the pcb "T-3242", also a green sticker with an "11" drawn over a "4" is seen. [photo="medium"]4401[/photo] ..

I don't know, but maybe it used a stud mount style transistor, like an MRF421, or MRF450A. This Amplifier is likely based on an Amateur amplifier like the "EB63" but an earlier incarnation. I wish I knew what Motorola RF Device Application "Note Book" contains a description/schematic of this old school circuit!!!?


[photo="medium"]4404[/photo] .
Surely a "Hooker" "Palomar" "Bimbo" and many others that said "Bi Linear" @ 100-150 watt rated boxes from this era look (almost) identical inside.?
Do you have an amp that looks like this?
[photo="medium"]4403[/photo] .
.
Any help identifying or information regarding transistors used in this "scrap box" would be greatly appreciated, I intend to restore it & add a "Motorola Inspired" AB thermal tracking bias circuit.
Thank You Once Again Guys. 73

P.S.: the possible factory wiring looks sloppy, so that makes me cringe a little.
-LeapFrog
 
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Thank you Big Kahuna, looks very similar, only obvious difference is the lack of stacked output transformers in mine. :)

This design looks like it might predate when feedback circuits were added to the common design used for these.
I highly doubt it is biased beyond Class C, but I do not know until I learn a little more.
 
I have the Bimbo model, uses a pair of TRW PT9784 stud-mounted finals. I've had it installed in a number of vehicles since the mid-70's and only ever had to replace a relay. the Hi/Lo switch on the Bimbo is labelled PEP/RMS and IIRC was switchable between 130W/90W output, but don't hold me to those exact figures, it's been a while.....
 
Those numbers sound about right for output from what I remember. You might want to do some google searches for those other models and see what TRW transistors were used and then try to figure out the motorola equiv. Not sure you'll be able to figure out exactly what was in there though - I did a google search and couldn't find anything on a squire 100, just some pics of the front of the squire 125
 
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The finals were the TRW makes of the Motorola MRF455A final (stud mount). 60W apiece. Stud mount finals are pretty rare. Unless you have a set handy, it wouldn't be worth it to resurrect this amp. You can't install the flange mount finals because they'll get a "hot spot" where the holes are located for the studs to go thru, and will damage the new transistors. Been there, done that. Best bet is to get an amp that has had flange mount transistors installed in it from factory.


~Cheers~
 
The PT9784 looks like a flange mount part, like the 2879 Which is good to see, because a I just got a
HB-140 Penetrator by: "AmComm" I might want to mod.
Thanks Guys!
 
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Best bet is to get an amp that has had flange mount transistors installed in it from factory.


~Cheers~
I plan on putting (2X) HG2879's in the "Perpetrator" (HB-140, from the other tread) they look like the same flange mount!

Do you think copper clad re-builds would be a bad idea considering the existing/etched circuit board in both the Squire (I'd go w/new heatsink) & HB-140?

The Squire or Penetrater could become a collectors item one day, it's too bad the top tin is missing, & this is a rough example in my opinion.(It's not beat up, just lacking that "complete" feeling)
I'd hate to de-value the amplifier by gutting it and installing a "2 pill copper clad setup", what do you think Exit13?
 
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Is it possible to unbolt the heatsink and turn it 180 degrees? It would give you a new surface to mount modern transistors to.

I wouldn't put a pair of 2878s on such a small heatsink without serious air flow. Unless you only use ssb.
It is a three piece unit (the heatsink) , turns out the HB-140 amp does not have a matched set of PT9784's (different lot #'s) & above a 20 watt carrier it started (self) oscillating!

The PT9784 hole may match a 2879!
I think it's ready for a modern rebuild, w/ HG's and a proper heatsink, I'll post some pics. (Of the filter board also)
Looks like I will learn how to machine aluminum &/or copper before this will be done!
I have a few heatsinks to pick from (undrilled)

Yes I could flip the Squire heatsink around 543! Great idea!
 
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I have one of those same amps. If you need pics of the inside of one, let me know Leap Frog. I have one that has the stud mount transistors in it. Same little amp, just a different name.
 
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I have one of those same amps. If you need pics of the inside of one, let me know Leap Frog. I have one that has the stud mount transistors in it. Same little amp, just a different name.
A photo of
the transistor would be sweet!
Thank you, 222DBFL!
 
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