Wet 1969 ITT-KB junior battery radio

[Refugee]

There is a photo of about half of the speaker way back in this thread.
Very little of it was left.
Edit Post#5.

[Philips210]

Thanks Refugee, I must have missed that one.

It looks terrible. I wonder if corroded batteries had some influence on this, in that the passivation was erroded and then severe corrosion set in.
My little ITT has corrosion on one corner of the speaker due to a cell leaking but obviously caught early.

Regards,
Symon

[Philips210]

Originally Posted by audion_1908

I don't think the speakers salvageable!

Attachment 204226

Attachment 204227

Attachment 204228

Attachment 204229

A bit different from this
Attachment 204230

Blimey, that's an understatement! I reckon the ship's radio speaker brought up from the Titanic is more likely to be serviceable than yours.

Regards,
Symon

[audion_1908]

Originally Posted by Philips210

Hi.

Out of curiousity, do you have any pics of the loudspeaker showing to what extent it's corroded?

Regards,
Symon

Ok here are some, it's all rust there is no good metal underneath! I was planing on trying to get it working and researched how to rebuild a speaker, but it's far to far gone!






The light is a bit better in the kitchen

[audion_1908]

Originally Posted by Philips210

Hi.

It's not too difficult but can be awkward especially if the can is corroded.

If you look under the can, and either side of the two screening can pins is a small tab. I find if you gently splay the screening can pins outwards that will be sufficient.
The following is far from ideal and I've never had a problem using this method but it's a case of using a blunt tool to apply gentle pressure on top of the ferrite adjustment screw. That should push the whole assembly out of the can. It usually comes out without having to apply too much force but could be difficult if the can is corroded. If shouldn't need so much force as to cause the screw to crack. Tapping around the base of the can first might help.
Once the assembly is out the polythene carrier has two tabs that can be splayed to free it from the base which had the winding. Under the base you'll notice the tuning cap. In the attached pics it should be clear how it is assembled. Note I've unscewed the ferrite screw for clarity, it's not necessary to have to do this. If you were to do the same then note its approximate position first so it's somewhere near the correct setting when reassembling it.

Others may have other ways to dismantle these IFTs.

Hope this helps.

Regards
Symon

Regards

The only tabs went through the PCB and where soldered to the PCB as an RF earth and mechanically fix it, I tried pressing it out with the adjustment screw, and pried at it with a screwdriver at the bottom of the shield, it was badly corroded I scraped the can clean and then scrubbed it with toothpaste.

[Philips210]

Hi.

Under normal circumstances just splaying out the flat screening can solder pins will allow the coil assembly to be pushed out. It seems what's stopping it is corrosion. You could try tapping around the base of the can.

Looking at the state of the loudspeaker it's a wonder anything is serviceable. I'd be surprised if those IFTs will be any good, though I think there's a wax coating applied to the windings so who knows.

Regards,
Symon

[Andrew2]

I've been stepping quietly past this thread for several days now, imagining it would be one of those 'after a quick dry-out and some new batteries...' types.
But I've just read through it and it's a real epic! When I saw those first three pictures I was going to tell you to scrap it and not drive yourself bonkers by even thinking of fixing it!
Your patience and tenacity deserve a medal!

[audion_1908]

Originally Posted by Philips210

Hi.

Under normal circumstances just splaying out the screening can solder pins will allow the coil assembly to be pushed out. It seems what's stopping it is corrosion. You could try tapping around the base of the can.

Looking at the state of the loudspeaker it's a wonder anything is serviceable. I'd be surprised if those IFTs will be any good, though I think there's a wax coating applied to the windings so who knows.

Regards,
Symon

The IF can had rust goo set hard from the speaker covering the whole of one side, the same gunge may have set hard inside, I may have to cut the can open.

The rust was all over there PCB, I had to excavate the components using a toothbrush, dvm probe and a resistor leg, the military-grade 1% resistors are great but I don't think the original designers would approve of my use of it lol.

The IF cans seem to be of a standard size in transistor staff, so could be possible to transplant and new shielding can on to the IF core,

[Philips210]

Hi.

See pic 1 in post #99. Note the flat screening can pins gently bent outwards. This should help to release the coil assembly. There should be no need to do any cutting of the can. Put the IFT on the bench and give it some decent taps around the sides of the can where it fits the base assembly. Then try gently pushing the coil assembly from the adjustment screw, it should then come out.

Regards,
Symon

[audion_1908]

Originally Posted by Philips210

Thanks Refugee, I must have missed that one.

It looks terrible. I wonder if corroded batteries had some influence on this, in that the passivation was erroded and then severe corrosion set in.
My little ITT has corrosion on one corner of the speaker due to a cell leaking but obviously caught early.

Regards,
Symon

I found no sine of battery's, the battery box screw was rusted and exploded when I opened it, but if the battery had a paper labels maybe they turned into corrosive slime?

[crackle]

Its like trying to get corned beef out of a can.
Mike

[PJL]

Maybe it's time for us to club together and get audion a replacement, a working example in good cosmetic condition fetches about £8 on ebay. We could desolder everything and supply it as a kit of parts

[audion_1908]

Originally Posted by PJL

Maybe it's time for us to club together and get audion a replacement, a working example in good cosmetic condition fetches about £8 on ebay. We could desolder everything and supply it as a kit of parts

Lol no that would be a waste of a good radio, thought would be a lot easier!

[Herald1360]

Originally Posted by crackle

Its like trying to get corned beef out of a can.
Mike

Not quite- there's no way to take a tin opener to the top end so you can push the contents out.

Not sure putting it in the fridge would help either.

[audion_1908]

Originally Posted by Philips210

Hi.

See pic 1 in post #99. Note the flat screening can pins gently bent outwards. This should help to release the coil assembly. There should be no need to do any cutting of the can. Put the IFT on the bench and give it some decent taps around the sides of the can where it fits the base assembly. Then try gently pushing the coil assembly from the adjustment screw, it should then come out.

Regards,
Symon

Thanks I missed the internal tabs, I had to apply an unreasonable amount of force but after prying Round the base of the can I got it off! It was full of white glue? I thought it was toothpaste, but did not smell minty and is not very water soluble but was tacky? The core looks to be intact, even against the odds.







I can't take a close up pictures with my phone

[Lloyd 1985]

I’ve got to ask, is there any continuity of the speakers voice coil?! If so give it some audio see if it makes a noise!!!

Regards
Lloyd

[Philips210]

Hi.

Good that you finally got it apart. The windings may be OK after all.

Regards,
Symon

[audion_1908]

Test setup




Tests side with 2 pins 4.7ohm 0.11mH with ferrite on, 4.7ohm 0.08mH without.
Tests side with 3 pins outer set 7.5ohm 0.35mH, 0.43mH with ferrite.
5.3ohm 0.10mH center to one side 4.2ohm 0.11mH to the other, both with ferrite

It looks like there is a tubular ceramic capacitor in the base, but doesn't seem to show up on the test?
The tubular ceramic capacitor appears to be wired across the outer of the three pins on the other side.
This seems to show the wires are good, but I don't know how to read the uncalibrated test gear results.
I think I'll consider all the other IF can good until proven otherwise as it's likely to destroy the PCB taking them all off! As the copper track has a tendency of coming off the PCB

I am waiting for some solder wick to turn up

And the ferrite core turns freely! It is a surprise that the cores seems to be ok

[audion_1908]

Originally Posted by Lloyd 1985

I’ve got to ask, is there any continuity of the speakers voice coil?! If so give it some audio see if it makes a noise!!!

Regards
Lloyd

There is no wire to the remanence the voice coil that I can find, and the rust has infused the paper core, it's not moving!
Do you want to have a go on the speaker? I will post lol

[poppydog]

Originally Posted by Andrew2

I've been stepping quietly past this thread for several days now, imagining it would be one of those 'after a quick dry-out and some new batteries...' types.
But I've just read through it and it's a real epic! When I saw those first three pictures I was going to tell you to scrap it and not drive yourself bonkers by even thinking of fixing it!
Your patience and tenacity deserve a medal!

As long as no other radios that could be put back into use are butchered to get this thing going again. The "transistor" radio seems to get in the neck on here more than the valve sets in that elusive search to make the perfect set.

poppydog