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Another Ferguson 3629 "Personal"

 
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Another Ferguson 3629 "Personal"

Post by Doz » Sat Jan 23, 2016 6:07 pm

Having precious few dual-standard sets, this turned up on eBay, and after battling with a woeful connection to the internet, I managed to bag this... a drive to Birmingham this morning bought it home, so I thought I'd have a quick look before wrestling with the loft ladder, and retrieving the Pye 169 in readiness for it's loptx transplant.

20160123_154654web.jpg

20160123_154937web.jpg


A snip of the mains filter cap, and up with some volts....

20160123_164940web.jpg


Some results on 405, poor frame sync and atrocious linearity and blank raster with occasional snow on UHF....

 
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Re: Another Ferguson 3629 "Personal"

Post by Lloyd » Sat Jan 23, 2016 6:20 pm

Very nice!

Looks to be falling apart internally like mine was too! The whole of the green part of the front can be unbolted from inside the cabinet and removed to re-attach the gold trim. Also, I can't remember which tuner it was in mine that was giving intermittent blank raster, or sometimes very snowy picture, but there is a tiny ceramic disc capacitor (7pf I think it was) with no legs, just the disc with some silvering soldered between 2 valve pins, and of course, the silvering comes off if you happen to waggle one of the valves! A blob of conductive silver paint fixed mine!

Talking of which, I don't know where my set has gone after this damned house move... :zx:

Regards,
Lloyd.

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Sun Jan 24, 2016 11:54 am

"Just a quick frame linearity fault" I thought... fatal!

Changed the cathode decoupling cap (C89, 100uF), checked the cathode resistor R112 (390 ohms) , fine. Switched on. Just as bad. :stm:

Spend hours last night pouring over the frame stage, Changed the PCL805. Still as bad. Then noticed some work had been done around there before (unsurprisingly). Must have been a Christmas eve call out ... R97 had been changed. A 68K had been fitted instead of 33K, and C68 had been changed (a 0.0047uF instead of 0.01). Also R103 had been replaced, but that was correct at 2.2Meg. Switched on. Much improved, but still not right, and now thermal! A quick squirt round with some freezer showed several of the supermold caps to be very reactive to temperature change, so they were all swapped out. Again, further improvement.

And that's as far as I've got, I can get it all nice and linear until I wind the height up. Then it loses linearity and frame lock.

It'll be a goon 'un when I find it !

 
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Re: Another Ferguson 3629 "Personal"

Post by nuvistor » Sun Jan 24, 2016 1:04 pm

There is a lot of TV in that small cabinet, they did well to squeeze a dual standard valve set in that cabinet.

Frank

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Sun Jan 24, 2016 1:16 pm

Got it !!!! :aad

A fresh pair of eyes this morning helped no end. Went through the circuit again, checking my work was correct. It was. Blast! :zx:

C92, an 'orrible 'unts , 0.01uF on the frame transformer output. Bingo. Could use a little centering, but now the controls are more-or less centred with good results.

... now UHF/625 .....

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Sun Jan 24, 2016 1:45 pm

625 is working... albeit gain falling off rapidly above ch.45. There seems to be a huge notch in responce between 45 and 60, gain returning at around ch 65, although much lower than that at 45. The tuner is very sensitive to movement. I think I'll remove it, and check the cap that LLoyd suggested earlier.

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Sun Jan 24, 2016 1:51 pm

nuvistor wrote:There is a lot of TV in that small cabinet, they did well to squeeze a dual standard valve set in that cabinet.

Frank


It surprisingly well spaced out. Except the frame stage (typical) which is underneath the mains auto-transformer and the frame output transformer, and behind the aerial sockets. Thankfully removal of the aerial sockets makes for improved access.

The 'unts on the frame transformer was a bit of a pig to do in situ.

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Sun Jan 24, 2016 2:44 pm

20160124_131331web.jpg


I think this is the cap you're referring to, Lloyd. Just next to the red coil. It seems good in this unit. I've cleaned up the valve bases and channel tuning drive, reassembled, and I can tune well throughout the range now, although there's some sound on vision to sort out, as well as strong background 100Hz hum, not so noticable on 405. I suspect more caps in the IF/ supply.

 
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Re: Another Ferguson 3629 "Personal"

Post by Rebel Rafter » Sun Jan 24, 2016 9:16 pm

Hi, all, RR here. I've seen that set and another one on ebay a few times, and I wondered what chassis and tube it had in it, is that one of the various versions of the 950 series or another one I've long forgotten? What size tube is that, is it an 11" like the one in the ITT/STC valve portable model? I had one of those once. RR.

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Sun Jan 24, 2016 9:52 pm

Rebel Rafter wrote:Hi, all, RR here. I've seen that set and another one on ebay a few times, and I wondered what chassis and tube it had in it, is that one of the various versions of the 950 series or another one I've long forgotten? What size tube is that, is it an 11" like the one in the ITT/STC valve portable model? I had one of those once. RR.


Hi RR, It's a plain old 900, with jelly pot, no cap dropper, and, as you say, an 11" tube. Later versions have a transistorised UHF tuner.

This one's getting there now. I've just finished evicting all the Hunts 0.1's, and now I've got reallly weak 405 sound! And my intermittent UHF has returned !!! Don't you just love it! :zx:

 
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Re: Another Ferguson 3629 "Personal"

Post by AidanLunn » Mon Jan 25, 2016 12:01 am

Doz wrote:
Rebel Rafter wrote:Hi, all, RR here. I've seen that set and another one on ebay a few times, and I wondered what chassis and tube it had in it, is that one of the various versions of the 950 series or another one I've long forgotten? What size tube is that, is it an 11" like the one in the ITT/STC valve portable model? I had one of those once. RR.


Hi RR, It's a plain old 900, with jelly pot, no cap dropper, and, as you say, an 11" tube. Later versions have a transistorised UHF tuner.

This one's getting there now. I've just finished evicting all the Hunts 0.1's, and now I've got reallly weak 405 sound! And my intermittent UHF has returned !!! Don't you just love it! :zx:


I would say it's actually definitely a 950 chassis but looking around on the internet I find a mix of comments that either say these sets use the 900 or the 950, so maybe the chassis was changed mid-run?

One thing I know, my own example of this model is definitely a 950 MKII.

 
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Re: Another Ferguson 3629 "Personal"

Post by Lloyd » Mon Jan 25, 2016 12:46 am

Doz wrote:
20160124_131331web.jpg


I think this is the cap you're referring to, Lloyd. Just next to the red coil.


That's the little devil!! Caused me no end of head scratching as to what to do about it. Good that yours is OK :thumb

Regards,
Lloyd.

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Fri Jan 29, 2016 5:25 pm

AidanLunn wrote:I would say it's actually definitely a 950 chassis but looking around on the internet I find a mix of comments that either say these sets use the 900 or the 950, so maybe the chassis was changed mid-run?


Definitely 900 this one. It's referred to as a "special", however

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Fri Jan 29, 2016 5:29 pm

UHF / 625 woes have been largely eliminated with a new PC88 in the UHF tuner, all channels now being well received, and much less "touchy" on the tuning.

A hum bar seems to appear after about 5 mins of operation, although it doesn't effect 405 operation as badly, so I'll continue my journey along the chassis, changing suspect looking caps as I go! I did read LLJ's article on the 900, and it suggested the PFL200 can go into grid current in 625 and give this effect, but substitution has proved it's innocence.

I've also glued and clamped the cabinet back together. Looking a lot more sturdy now.

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Fri Jan 29, 2016 7:00 pm

C100 1u 350V was guilty of the hum bar.

Sat there watching for a few minutes, when sound and picture vanished. R136, 12 ohms had failed. Replacement restored viewing. Switching to 405 provided great pictures, but much lower sound that 625, and very distorted. Stupidly I tweaked L28 & 29 to no avail, they seemed to peak up OK.Switched off and pulled out V6 and fed 38.25 MHz (1KHz modulated) into pin 7 from the signal generator, and scoped up the sound output on pin 5 of the can. Peaked it back up. Refitted the EF184 and switched back on, poor sound on 405, 625 fine.... Lent on the aurora by accident... sound restored !!! Duff lead :stm:

Set's been working wonderfully for a while, time to put the back on and tempt out those remaining faults! :aak

 
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Re: Another Ferguson 3629 "Personal"

Post by Katie Bush » Fri Jan 29, 2016 8:47 pm

Doz wrote:
Set's been working wonderfully for a while, time to put the back on and tempt out those remaining faults! :aak


The most feared part of any restoration/repair project........ :aaj :aal :aaf

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Fri Jan 29, 2016 9:34 pm

Katie Bush wrote:
The most feared part of any restoration/repair project........ :aaj :aal :aaf


Yep, intermittent frame collapse. Only with the chassis in .... :stm:

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Fri Jan 29, 2016 10:40 pm

Chassis out and it's fine, tap about with the old screwdriver handle, as firm as a church.... wiggle the wires to the frame coils.... gotcha...

Bridge out the wires with some crock clip leads.... still the same ... tap the scan coils themselves ... aghh!

For one awful moment I though the coils were duff.... then I saw a tiny arc.... That wretched thermistor had turned into a blob of something not quite thermistor like anymore....

thermistor web.jpg


Duly shorted it out.... had to reset the frame height and linearity quickly, but service resumed!

625 web.jpg

405 web.jpg


Excuse the usual shocking state of the photography.

 
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Re: Another Ferguson 3629 "Personal"

Post by nuvistor » Fri Jan 29, 2016 11:46 pm

Great job, I don't have a circuit, what job does C100 do?
Frank

 
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Re: Another Ferguson 3629 "Personal"

Post by sideband » Sat Jan 30, 2016 8:50 am

Good job Doz.

I'd really like one of those but they are either too far away or the price is way beyond what I'm prepared to pay for one.....

 
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Re: Another Ferguson 3629 "Personal"

Post by AidanLunn » Sat Jan 30, 2016 9:07 am

The 405 performance on these (I speak for the 950 chassis version) is amongst the best I've seen for 405-line sets - very contrast-y picture. Without any fades to black you could almost believe it has proper black level (it doesn't, it's mean level again).

Not only that but you can fit them just about everywhere, so mine doubles up as a pedestal for my computer monitor :)

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Sat Jan 30, 2016 10:33 am

nuvistor wrote:Great job, I don't have a circuit, what job does C100 do?
Frank

Decouples the HT rail.

 
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Re: Another Ferguson 3629 "Personal"

Post by Michael Watterson » Sat Jan 30, 2016 12:03 pm

sideband wrote:Good job Doz.

I'd really like one of those but they are either too far away or the price is way beyond what I'm prepared to pay for one.....

Me too!

 
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Re: Another Ferguson 3629 "Personal"

Post by sideband » Sat Jan 30, 2016 2:05 pm

sideband wrote:the price is way beyond what I'm prepared to pay for one.....



There is one on eBay at the moment but at the price they are asking......! :ccf

 
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Re: Another Ferguson 3629 "Personal"

Post by Doz » Sat Jan 30, 2016 3:57 pm

sideband wrote:
sideband wrote:the price is way beyond what I'm prepared to pay for one.....



There is one on eBay at the moment but at the price they are asking......! :ccf

Been around for a while, that one....

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