Taylor 94A Test Generator

[OldTickTock]

I've been after a 405 Test Generator for a while eventually managed to get hold of one and with so many extras too, It's Taylor 94a waveform and alignment generator.

features:
405, 525 & 625 lines, TV alignment patterns,wobbulator,A.F. tone.Covers bands 1 and 3, FM signal generator, sweep oscillator, continuous wave generator, AM signal gen, audio signal source.

All present and correct, well almost, just minus one valve a EF95, typical I have what I thought was quite a large and varied collection, however as always it's the one valve I have not got. It came with a full schematic too.

Had to remove the Taylor Model 22 and AVO 7 from the bench to a higher shelf to get the beasty in place and it weighs a lot.

Looking forward to giving it a run through once I have the valve.

[OldTickTock]

Hi Trevor,

Thanks for the very kind offer I forgot to ask if you might have one. I ended up purchasing 3 from Jeremy (Pamphonica) hoping they will turn up today so I can have a play. For clarification Jeremy kindly manages a pool of valves which were kind donations and all proceeds are then passed on to the BVWTVM British Vintage Wireless and Television Museum (Gerry Wells)

Chris

[Bushbaby]

Hi Chris
I have number of NOS EF95's too and I would have offered them at P&P only as well.

Regards

Rob

[OldTickTock]

DOH! double DOH!

[OldTickTock]

The valves turned up yeah

I Fitted the missing EF95 then did some initial checks heater chain continuity is there, main smoother/reservoir electrolytic looks ok so connected to the Variac and wound it up to 80V left it for a few mins before winding up to 120v, few more mins then went to 240. Pilot lamp was dead so replaced 6.5v 300mA lamp all ok The valves were glowing nicely so I connected it to a 405 TV but nothing happening when connected to the TV set.

Opened it up and OH! My! GOD!! what a rats nest of components, lots of Lozenge Dubiliers, many shiny black Plesseys, a few HUNTS, one large flat waxy A few TCC metalpaks/metalmites and a few GEX34 diode thrown in for good measure, looks like they decided to use anything and everything in this and all the crappy caps to boot, still hindsight is a marvellous thing and they certainly would not have expected the generator to be still in service 50+ years later. Finally to add to the mare and make things harder, resistors all tightly packed around everything with lots of wires and looms, now I see why I started to like PCB to hard wired chassis.

The unit also packs in quite a large mains TX and 20 valves, 12 of them being ECC83's ( if the valve robbers had got their paws on this) I now can see why the case has so many vents one every surface bar the front.

I changed the following caps as they were very sick looking and seemed a good starting point

Big flat waxy a 1000pF no change
One large .5uF HUNTS no change
one TCC metalpak electrolytic 8uF

Ahaa steps in the right direction, I can hear the what sounds like a TMB working now.

I have it connected up to the Fergy TV I've been working on (confirmed it's ok with Testcard C) and, nothing although when I switch the Taylor through all its 10 different outputs ( hoz bars, grid1, grid2 etc) the screen blips as I turn the taylors control so something is sort of there.

This is going to be a long fix as all the other caps are so buried a mass disassembly will be required. I guess it would have been boring if it had worked, but to be honest I would have preferred it to have, restoring test equipment is not my bag or idea of fun......oh well deep breath!

Chris

Edit: with the front panel removed I get some reasonable access to some of the caps, but the ones at the rear are another matter, I will have to put my thinking cap on for the plan of attack on those. Luckily I do have an original manufacturers schematic to work from

[tiv48]

my god good luck
rob t

[OldTickTock]

Well some progress made today, I've got it sending out some bars. Concentrated on the line/frame and video stage of the device and it seems to have helped.

The video stage has a couple of GEX34 diodes, I tested these in situ with the DMM the passed but I think I shall replace these next and I shall start to replace the caps in the freq oscillator and modulator stages.

This certainly is a test of your dexterity with a soldering iron, trying to avoid burnt fingers and melted wire sleeves. I have in a few places had to cut the old components leaving a tail then making a coil on the new component to sleeve the old tail,times like this Cols' mini wire tool would have been useful.

Onwards...hopefully more results tomorrow

Chris

[Mark R]

Coming along nicely Chris, reminds me of a Mullard HSV tester I have for doing........so many resistors I went almost colourblind!

cheers Mark

ps no the Mullard is not fixed!

[Hunts smoothing bomb]

Hello Chris,

What a beast that is, I noticed the screening cans for the valves are missing, presumably you have taken them off?

It's looking good so far, nearly there.

Cheers
Lee

[OldTickTock]

Hi Lee short answer is no, and this is turning into a mare. I think it's been got at before. Clues missing screening can's, missing EF95 and delving deeper into the rats nest two wires snipped and white tagged. I've done the major recap and it's not producing anything more. The oscillator sounds as if it's working but when I poke around with my Taylor 22 (signal tracer) i cannot find anything. One of the ECC83's decided to go purple on me quite why I don't know, fitted a replacement and it's fine.

I'm going to have break from this as it's beginning to pee me off, and I want to get back to my main interest TV's and finish the Fergy, might have a clearer head in a couple of months and feel like tackling it again.

Chris