I've just about finished a resto job I normally wouldn't have started,,,,

The thing is a Precedent 3 in 1 from 1971, marviplate case, chipboard base, 25" Philips CRT and an Astor Series 11 chassis. Not an item I'd normally collect but Rosemary likes it, it has an interesting model history and it just needed to be rescued.

These were made by AW Jackson Industries in about the last year or so of their existence, using cast-off Astor chassis full of Anodeon transistors. Astor themselves were using Philips transistors by then, subsequently using the Philips all solid state chassis that had been designed by Pye.

Anodeon transistors did not enjoy the best of reputations! And the devices in this chassis suffered from a further setback which I will reveal later in the story.

CRT checked out strong. So I blew the 10mm thick carpet of dust from the PCB, replaced the down-to-air 6AL3 and expected to get a raster.

Nope.

So I dived into it, first correcting the dodgy previous repairs.

No horizontal drive. A BC547 fixed that.

No vision or sound. More bad Anodeon transistors holding the AGC way out of range.

Still nothing, Voltages around the BF167 and BF173 pointed to them both being open circuit. But wait, these were Philips parts! How is that possible?

On removing them, the wires were rotted away. Then I realised what had happened. The chassis was home to mice at some point in its life. Mice did what mice do, on the dust carpet, which attacked the lead wires of the transistors, mainly in the IF stages.

Now BF167s and BF173s are made of unobtainium. The all-plastic BF199 is a suitable replacement but I had neither. So, noticing that the fT of a BC547 is 300mHz, I thought I'd give them a go in the IF stages.

Sure enough, we now had a little snow. Tuning into my Ch7 modulator and adjusting the AGC, I now had a signal. Unlocked and no sync.
Another BC547 in the sync separator. Success! No sound? You guessed it, another two in the sound IF fixed that.

Vertical oscillator was drifting out of range of the control. So I soaked the blocking oscillator choke in WD40 and left it overnight. Next day that was fixed.

Time for a session on the big CRT.

This did not go so well, the set was very fussy about signal levels at the antenna, my macrovision-stripping modulator didn't have enough drive and the Ch7 one had too much, causing picture pulling. A nice picture could be obtained by fiddling with the antenna coupling (an adjustable attenuator would have been nice) but the set didn't have the gain or performance I knew the albeit simple Series 11 chassis was capable of.

So, found some BF199s at Wes Components. They arrived and are waiting for a spare hour or so to finish the job.

Watch this space, I suppose!

BC199 or BF199 ? I'm confused.

Definitely BF199! Typo, will correct.

Ian!

Just use more WD40!!!!
That will sort it.

Fascinating read let us know how it goes please............

Fred.

WD40 definitely made it work again! With the paper-phenolic PCB soaked with mouse urine there were leakages happening everywhere.

Why did you say that Ian,
Now everyone is going to advocate WD40 as a fix all for everything, cause they saw it on a forum.
Including on your breakfast cereal.
Has its purposes and very useful, but as you know sprayed everywhere becomes a service mans nightmare.
Especially on IF transformers and potentiometers.
Had not considered its mouse urine cleansing properties.
JJ

Yes, sorry, I agree with you.

That stuff was the bane of our lives when lazy TV techs would spray it into TV tuners, completely de-tuning them.
They'd require a strip down, thorough wash and dry, contact clean with metal polish followed with a WIPE (not a spray) of CRC or similar.

Like anything, it has its place.

But it did fix the noisy pots in this chassis. I hope it lasts, where would you get a 3 meg PCB mount tab pot these days?