Philips 219B two from three

[davek0974]

Ok, have decided to try and get at least one of my three Philips 219B's up and running, maybe even two.

Pictures attached are of the three donor chassis, still in the cabinets.

As you can see one has a speaker missing, one has all the valves missing but that leaves two speakers and two sets of valves - this is assuming all the valves are ok and not fried.

All the cabinets and glass dials are in good condition, all back cards are missing.

I think the PSU from my pantry transmitter project will be able to give the HT but will need to mess about a bit for the 2v heater supply.

I would like to do an alignment if I get that far so I need an RF signal generator as ii don't have one yet, anyone recommend a unit and/or source??

[HamishBoxer]

Dont worry about IF alignment as chances are it will be fine once everything else is up and running.
If it has not been twiddled that is.

[davek0974]

Probably would be ok, but just like to learn and expand the toolkit on each job

I'll check the heaters on the valves for resistance first, then order up a full set of caps etc

I gather with an HT of 120v, the caps won't need to be any more than 200v working?

[Herald1360]

160V would be fine, but 400 or 630 won't cost much more and will be more convenient size wise. Except electrolytics where 250 is about as high as is sensible for HT parts and similarly up to around twice the rated voltage for lower volt types.

[davek0974]

Ok thanks,

whats the recommended way to mains power a battery set??
needs 2v and 120v, i think the 120v will be pretty easy but don't want to risk over-running the heaters.

[Herald1360]

Ideal 2V is a "Cyclon" lead acid rechargeable cell, or just one cell of an old style car battery with external links. Otherwise a 2V regulated dc supply. Given that the load is constant, a couple of D size alkalines (3V) and a suitable series resistor will do.

A few more specific ideas here:

https://www.vintage-radio.net/forum/...d.php?t=105668

[G8UWM-MildMartin]

http://www.vintage-radio.com/project...y-set-psu.html is worth a look for power supply ideas. The LT regulator has resistor values calculated for 2V and it's easy enough to add an extra multiplier stage to increase the HT to 120V if required.

[davek0974]

Thanks for that, interesting ideas there especially the linked PP3's

Wilt started as soon as i have re-capped the set i'm working on now.

[davek0974]

Full set of caps on order, comes to £30 a go so only ordered the one.

Should get started in the next day or two

[davek0974]

Hmm, ever get that feeling......

After an hour or so, I finally managed to get two chassis extracted, the knobs have taken a beating as the grubscrews have rusted solid and split most of the bushes, I have salvaged two wave-change knobs and one and a half tuning/volume knobs - going to need some work on these.

The chassis are in pretty bad condition, damp has had a go, as has woodworm, one has been butchered and a couple of the valves soldered into the sockets although the guy did leave a nice little tag with "valve soldered in" on it - very old.

The last chassis pictured is my chosen target - its not too rusty and the dial cords are still intact, speaker is missing but i have two spares, and most importantly the valve bases seem pretty good and firm.

My next step is to get in the garden and have a go with the compressed air line and stiff brush to shift most of the crud and dead spiders.

Then, well i'm not sure now - guidance please.

Do I make a new front panel, the existing ones are delaminating, but this will wreck whats left of the speaker silk, the one shown is one of the worse ones.

Should i strip way down - panel, dial, pointers, etc all off and clean up the metalwork and so on?

I have not tackled a job this deep/severe yet so its a learning curve, I think the re-capping and wiring is going to be the easy bit.

On a good note, all the valves salvaged so far have tested good on the heater filaments and all the bases/top caps are still firm.

Any pointers gratefully received.

[davek0974]

Anyone got any pointers, ideas?

Should i rebuild the face panel and find something suitable to replace the speaker silk or just clean up, re-cap and stuff it all back in the cabinet

Not sure how far to go with this...

[davek0974]

Got the target chassis stripped out today, cleaned and blown out, tuning spindle oiled and smooth, on/of switch working again as it was seized up, wave-change moving ok now, indicators all moving ok, dial glass cleaned and dial frame cleaned.

The glass was in a bad way, covered with what was likely cigarette tar, cleaned up pretty well, a couple of the stations on one edge are pretty feint now but at least it didn't all wash off

Removed a speaker from one of the other chassis so I should have a complete set of bits now. The plywood front panel in the target set was de-laminated and dead so i stripped one from a donor which seemed very good apart from a small burnt area on one edge - my only guess is that at some time in its life a soldering iron was rested here as there are no parts inside near that area

The grille cloth was peeled off and gently washed - looks much better but still 'old'. Need to start running some new wiring now to replace the cracked rubber insulated stuff, caps should be here Monday.

[davek0974]

Been looking at the wiring, i think i'll start at the battery leads and work my way in

Already see signs of modifications/repairs - the big 50uf electrolytic cap in the middle of the chassis has had one of its leads snipped and been replaced by an even bigger(physically) 16uf one strapped to the O/P transformer. I think a modern 50uf will easily fit back inside.

Question - why would the HT- be fed via a MES bulb? It's not on the digram but they all have it

Only reason i can think of is some sort of surge suppressor to assist while the large grid bias caps charge up maybe?

[Simon Gittins]

A bulb was often used as a fuse in battery sets.

[davek0974]

Ahh, makes sense, not on the diagram though - after thought or service mod

[davek0974]

Got most of my caps today, i missed a few out and two of the ones sent are wrong, oh well

Whilst poking about i discovered one half of the OP transformer primary is open circuit, hopefully one of the donor sets will yield a good one, I guess thats a common failure following failed caps etc?

[davek0974]

One of my donor set OP transformer also is open circuit on one side

Thats a bit worrying as i only have one more and that's not as good as it has flying-lead connections and the insulation is ********, also not tested it yet.

Looking at the diagram, it seems a pretty normal push-pull output, centre tapped transformer, but the same winding is open on both transformers - seems odd?

Is there a common failure point ??

[Herald1360]

It'll be a low power fine wire transformer, so it's possible that damp storage and corrosion could see off one end of the primary winding. Fingers crossed- it would be a pity to lose the best feature of the set.

A rewind is possible, but might not be economically attractive.

Just looked at VVT to find that they no longer do transformers (Their "Firefly" model looked possible).

http://www.vvttransformers.co.uk/news.htm

[davek0974]

Yes it could be the outer winding maybe or the inner, maybe a connection there. Both are open circuit on the same winding. Will check the dodgy looking spare out later. Judging by the look of it, if it did check ok, i would likely have to snip the leads close and fit new ones, the two broken ones have nice easy terminations on the top insulator.

[davek0974]

Got the OP transformer stripped out and luckily it measures good on all windings Under all the muck it was the exact same type as well, the solder pads were hidden under a load of muck.

After wrestling with rusted up screws for an hour or so, finally got it fitted into my chassis so it's just about ready for power, is it worth measuring out all the resistors first or just go for it?

Need to sort out a PSU first, time to visit the pound shop for some PP3's.