Bush TR82C.

[pwdrive]

No worries, an RF signal generator can be obtained for reasonable money from the likes of Ebay etc, but you need one that is described as fully working, don't buy a cheap (or expensive) duffer.

An Advance E2 is a good old industry standard, it's a valved sig gen not a transistor one. Another popular one seems to be a Leader sig gen, this as far as I know is a transistor jobie, I think they are often re badged under different manufactures names. I have never used a Leader but have used the Advance E2 many many times.

Either of those will cover all the frequencies that are concerned with domestic radios, they have a modulation facility, this is important if you are considering any other make, the modulation facility allows you to modulate the RF signal with an audio tone generated by an audio generator, the audio generator is already built in as part of these generators.

You don't need to be a boffin to operate a sig gen it is easy to learn, most folks on here can talk you through it if need be.

Lawrence.

[mightyzorg]

An easy way to check if the RF alignment is in need of adjustment on Medium wave is to tune to a station at around the 200 to 250 meters markers on the tuning dial then to gently touch the medium wave aerial coil on the ferrite rod (try touching both to ascertain which is the MW coil). If the signal gets louder then RF alignment is almost certainly needed, if it stays the same or drops then it's probably ok I appreciate that this isn't that easy on a TR82 unless the chassis is out on the bench (if the chassis is out then you won't have the tuning scale to guide you so the tuning capacitor needs to have the vanes almost fully Unmeshed to be at the 200 to 250 meter part of the MW band)
Oh, yes, Use a finger to touch the coils, no risk of shock .

All the best

Rob

[lol30]

hi all
have checked the resistance on the coils & the switch side of c3 & the reading i am geting is all the same 0.00 does this sound correct ? & yes tried the tuning on mw & lightly touching the aerial makes a huge difference to sound output.
kind regards & merry christmas to all.
laurie

[mightyzorg]

From what you have just mentioned, I am pretty convinced that a full RF and IF realignment of your TR82 will restore its performance. Ideally you would need a signal generator as mentioned in previous posts but with a little care and knowledge of where stations local to you should appear on the tuning scale it's not too difficult a task. (for example, Here in North Wales, I use Radio wales on approx. 450 meters and Magic which is about 198 meters, this I find is more than adequate for domestic receivers. Of course, you must study the alignment procedures carefully and identify the trimmers that you may need to adjust before starting.

Rob

[Joe]

If you're feeling brave see: http://golbornevintageradio.co.uk/forum/...p?tid=2752

- Joe

[pwdrive]

The low ohms readings will depend on the minimum indication that the test meter can resolve, they can vary between types and makes.
On the face it looks like you have low ohms readings which would indicate that the coils are ok.

It is possible to tweek the RF alignment without a signal generator, if you look at the manual the RF alignment instructions are in there.

In all this we are assuming that the radio is in a good or reasonable reception area....

Before attempting any RF alignment you need to check that the Oscillator is running at the right frequency, you can check this without a signal generator, tune to a known station near the low end of the band and then one near the high end of the band, these should more or less coincide with the correct position on the tuning scale, most station frequency/wavelengths etc can be found on the internet. If the stations are to weak to identify then connect a few feet of wire to the external aerial socket (Skt 1) If all is ok then you can proceed.

There are two RF adjustments for MW, one will be for the RF tuning coil on the ferrite rod (L4/L5 assembly), to adjust that then first make a reference to where the coil is on the ferrite rod, you can do that with a pencil so that the coil can be returned to its original position if needs be then tune the radio to 600Khz (500 meters) with the radio switched to MW, if there is no station at 600Khz then adjust the coil assembly by sliding the coil former either way along the ferrite rod for maximum background noise, you might have to crank up the volume, be careful not to force the coil, be careful not to damage the coil windings, the coil former might be sealed on the end with some wax or other substance to the ferrite rod or it might have a thin piece of material running between the coil former and the ferrite rod, either way you will need to make the assembly slidable along the rod without excessive force.

Once that is done then you need to tune the radio to 1.5 Mhz (200 meters) then adjust TC4 for maximum background noise. TC4 is the MW RF Trimmer, that also might be sealed with either wax, a blob of paint or varnish, any seal should crack off when you adjust the trimmer. Before you adjust the trimmer make a note of the position of the screw or nut and also the direction and number of turns you adjust it by or parts thereof either clockwise or anti clockwise so that it can be returned to it's original position if needs be.

These two adjustments are interactive so you might have to do them both a couple of times in succession to obtain maximum background noise at both alignment points.

Lawrence.

[Robert Darwent]

Touching the aerial coils on any portable radio will give a noticeable increase in signal strength as you are effectively using your body as an antenna - it's exactly the same as plugging a wire into the antenna socket.

It does not (necessarily) mean a RF or IF alignment needs performing - you could make things much worse especially if you've never done an alignment before.

Being specific to Laurie's TR82C, it would be very unusual if all the alignment in the set was out - unless of course a "twiddler" has been in there at some time.

Regards

[pwdrive]

Forgot to say in my last post:

The RF coil on the ferrite rod should be slid along the rod with a non metallic tool, usually a plastic knitting needle filed to suit, your hand must not be touching near to the coil as this will add stray capacitance and can be misleading.
The RF trimmer capacitors screw or nut will normally be at signal earth potential so you can use a small screwdriver or whatever to adjust.

In all this I am not saying go ahead and try it, just explaining the relevant points, bad RF tracking is in most cases due to the coil having slipped on the ferrite rod due to a knock or vibration over time or the phantom twiddler has been at it, the cuckoo in the nest would be a specific connection/component failure ie: open circuit capacitor or one that has lost part of its value.

Lawrence.

[mightyzorg]

Touching the aerial coils on any portable radio will give a noticeable increase in signal strength as you are effectively using your body as an antenna - it's exactly the same as plugging a wire into the antenna socket.

It does not (necessarily) mean a RF or IF alignment needs performing - you could make things much worse especially if you've never done an alignment before.

Being specific to Laurie's TR82C, it would be very unusual if all the alignment in the set was out - unless of course a "twiddler" has been in there at some time.

Regards

I have found this not always to be the case, in fact, on nearly all the portable sets that I have repaired, if aligned properly, touching the aerial coils will usually result in no discernible difference or a reduction in signal. What I have found though is that if the coils on the ferrite rod appear to be undisturbed, then usually, the set either needs a quick tweak at the high frequency end (with trimmer caps as these are more likely to be twiddler friendly) or the oscillator has been fiddled with and re aligning this will bring the stations back to their proper positions with a resultant increase in signal if nothing else has been disturbed.
I have had several TR82s where a phantom has been at work and realignment has provided a complete cure.

Best Wishes
Rob

[pwdrive]

In the past I have often found that if tuned to near the top end of the band then the effect of hand effect aerial gain is negated by the detuning effect due to the stray capacitance introduced and down the bottom end of the band sometimes a slight increase in signal strength is possible due to the hand aerial effect but the detuning effect is less because the tuning capacitor is near full capacitance, but all in all not a great deal of difference if aligned correctly and pointed in the right direction.
Having said that I haven't worked on ferrite rod radios for years since I was in the trade, all my radios are old comms receivers.

Lawrence.