Pennine Ranger Project

[boater sam]

Got a Ranger by default. Rough, but glass dial is good, unmolested chassis.

Very dead due to reservoir and smoothing caps. AF coupler cap changed too.
EF39 unstable, motorboating. Fresher one gets some reception but nothing on LW. ( Why are most EF39s shot? )
Bit of IF transformer twiddle brings levels up astoundingly. Still no LW
So fairly good so far, nice bandspread and tuner slow motion drives.
BUT
Needs a back board and I cannot find a picture of what it should be like. 
Had to force 2 knobs off, screws will need drilling out, one knob missing altogether.
Cabinet is whole, but will need total strip and refinish, its a cheap thing but the front is a pretty combination of wood veneers.

[Mike Watterson]

( Why are most EF39s shot? )

Are they? I've never had to replace one. Maybe you've been unlucky? EBL31 though

Output valves suffer the most from leaky caps.

Is it this?
http://www.radiomuseum.org/r/pennine_ran...43e54.html

I'd never heard of a Pennine Ranger.

[boater sam]

That's the one, the firm is still going, make amps and transformers etc. in Huddersfield. Its quite a cute set, dual AVC lines! And EL33 output valve.

I do seem to have a lot of unstable EF39s. even the ones which still have metallising mess with me. Tried tinfoil and screening cans (cut up Coke cans ) without much success.

Got EBL31s if you are stuck, including genuine short ones.

[boater sam]

Still need a photograph of the back panel of a Ranger woody table radio made by Pennine post war.

Does anyone  else own one or know of one I could photograph please?

[Murphyv310]

Hi Sam.
Although not a direct equivalent a 6K7G will usually work in place of an EF39.

[boater sam]

Yea, verily and a KTW63. Had to do that sub on the HMV 1200 motor tuned. I don't seem to have a lot of luck with EF39s, is it just me? 

[boater sam]

Had a ticklish afternoon with the Ranger, its an E54/3 incidentally, trying to find long wave.

Aerial coils and wave change switch seem OK, local oscillator stops I recon  when in the long wave position but the oscillator coils have continuity. The medium and long wave oscillator coils are on top of the chassis on an open tag strip arrangement with small adjustable core slugs. 
Careful dismantling revealed that they are pairs of coils in pairs of round half cup ferrite pots. 
The ferrites on the long wave coils are cracked, top one in 2 pieces, bottom one in 4. These are only about 16mm od and the coils are wave wound with very thin cotton covered wire. There is rusting and the cores were stuck in the coils.
I managed to work the cores out, and get the bits of ferrite off the coils, after a few heart stopping moments when things got stuck, without breaking any wires off.
I have superglued the bits back together, tomorrow after going to the Gnosall meeting, I will see if it works.

[Murphyv310]

Feedback cap in the oscillator most likely dropped in value usually100pf or thereabouts.

The metalising can get a poor connection to the valve base and cause instability. Usually the wire doesn't contact the coating.

[boater sam]

Now I don't usually struggle with a radio, but, this one is being difficult.

Tried to rejuvenate the Hunts 16 - 32uf can, got to 4mA then it started warming and creeping up, so cut it and emptied it. Plenty of empty space around the sweated core, stuck in tar at the bottom, not connected to the can at all despite it saying "can not isolated". Drilled holes for wires in the 3 tag rivets and fitted 20uf & 100uf that were at hand. Put it back with the cut in the clamp, invisible repair.

Found an open circuit medium wave coil, managed to pick up the end and fixed it. Strange because it worked as it was on medium wave!
 Changed the long wave oscillator coil shunt cap. 100pf gone to 23pf, checked all the trimmers for shorts, replaced the triode grid cap, cleaned the wave switch. Tried padding the long wave coil to see if it was just miles out of tune as the ferrites are in bits glued together. All coils are intact and no shorts to ground.
DMM on the triode grid kills the oscillator on all bands, so it may be a scope job.

Its fine on medium and short waves but long is just hash getting more strident at the high frequency end. Aerial on the mixer grid gives the same results. Its got to be in the oscillator coils somewhere, but where?

Out of my 11 EF39s only 2 work, the rest go unstable and its not due to the metallising not earthing.
Its not decouplers either, I just have no luck with EF39s, may move to 6K7Gs.

So if anyone has any ideas, please shout up.

 

[boater sam]

Another few hours on this set today. The local oscillator does run on long wave but not very well, only -0.2v on the grid and it stops at the low frequency end whereas on medium and short waves there is -2v.

I've checked everything on the wave change switch and all the coils and found nothing so I am assuming that because the ferrite pots are broken on the long wave oscillator transformer coils the Q is so low that it stops it oscillating. So that would seem to be an impasse, finding another for this rare set is not likely. I'll pretend it is an export model!