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Old 12th Jun 2006, 10:22 pm   #1
Zelandeth
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Default Kolster Brandes KV024 (VC51 chassis)

This was donated to me by a close friend who was clearing out a house for sale. He knows I've a soft spot for older tech, so asked if I was interested...too right I was! Been meaning to get hold an old TV for ages.

http://zelandeth.artamir.org/compute...frontsmall.jpg

Got a page full of images right here if you wish to look further.

So far I've corrected a few problems:

[] Disconnected mains lead (was a bit of a no-brainer that one - the little red wire hanging off the power switch gave it away).

[] Missing PCL85 valve. Took a bit of working out that did!..but THINK it's the right one.

[] Fixed (temporarily) broken wire from mains dropper resistor.

Then, after checking as much as I could, decided it was time to see what happened...and fed it some power. The result the first time was somewhat offputting, as it was before I'd replaced the missing valve, and absolutely *nothing* happened.

Having now replaced that I was rewarded with all the tube heaters (DY87 in the EHT cage excepted) and the panel lights (which switch between the two tuning dials depending whether you've got 405/625 lines selected...cool!) lighting up. No picture or sounds of life from the HT side however. I know that a 30P19 valve in there looks as though it's got a suspect vacuum however, so it may be partly responsible. Heater does light up in it though. I *think* there is a very soft sort of hissing noise from the flyback, maybe an indication of some sort of life? Afraid a high voltage voltmeter isn't something I yet possess, so I'm not gonna go poking that!

Walking into the set in the middle of the night, I've managed to break off the top of the height control pot too...so will have to replace that! At that point it got moved to the opposite side of the room, hopefully preventing any more disasters. All of the front controls need new shafts though, as they've gone brittle...the 405 fine tune control was superglued on when I got it, and since then the power/vol control and both tuning dials have come off in my hands!

Apparently the set has been in storage for at least 20 years (how long the house has been empty), and it looks as though it's had at least two repairs in the past, a big RS components electrolytic cap under the chassis, and a couple of rather non-original high power caps attached to the dropper tend to make me think this.

The only other thing of this period I've resurrected was an old Grundig TK-14 tape recorder...and that was somewhat simpler in construction than this! Was just a matter of replacing a valve there too!

So folks...where do I start? That's the main question! I tend to think replacing the suspect valve is somewhat of an obvious one (though I do need to find one!). Re-capping will no doubt be on the cards given there's quite a number of paper caps there appear to be in there...mostly nicely tangled in that rats nest under the bottom cover too...D'OH! Any tests I can do to verify whether the flyback's intact? If the EHT side's toast, guess I'd be kinda stuck.

Additionally...can anyone date the thing? The cabinet styling's not like anything I've seen before (the sets of the original series of Star Trek aside...), and the somewhat futuristic (and in my view rather smart) styling doesn't seem to quite fit the technology inside. The serial number is 1372/11775 if that's of use.

Finally...anyone got one? I've not even managed to track down a single photo of one of these on the net so far, would be really good to see one in operation, or hear from other owners of the KV024. I'm determined to get this set back to working condition - it's too nice a set not to.

I could be wrong here, but would I be right in assuming that this wouldn't have been exactly a cheap item when it was new? To me it just *looks* classy.

Thanks in advance!
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Old 12th Jun 2006, 10:34 pm   #2
Dave Moll
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Quote:
Originally Posted by Zelandeth
can anyone date the thing?
Radio & Television Servicing would appear to imply a date of 1968-69, with details of the STC VC51 chassis in this and the previous year's volume.
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Old 13th Jun 2006, 9:15 am   #3
BassoonBloke
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Smile Re: Kolster Brandes KV024 (VC51 chassis)

Hello there,

Nice set !!.
Looking at your other pictures i would say that the 30P19 Output valve is probably fine, I've seen a few that have the grey/reddish coloured gettering and work fine, you'll soon know when you get some HT flying around (nice bright blue glow in the valve if it's had enough!!).
I would start by checking out the big dropper reisistor as it looks as though it has already had some repairs. Check for continuity. These rarely go much above 5K. You can usually see which parts of the dropper are connected to each other and work out part of the circuit yourself.
If you can get the input / rectifier and power distribution sussed you should be able to get some HT on the way.
Good Luck,
Lets have some pictures of it when it's up and running,

Alan.
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Old 13th Jun 2006, 10:44 am   #4
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Default Re: Kolster Brandes KV024 (VC51 chassis)

I'm sure the KV024 was marketed as the "Deep Scene" model. I think there was also a RGD version.

DFWB
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Old 13th Jun 2006, 2:56 pm   #5
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Correct it was the "Deep Scene" model.
I have a set with the VC52 chassis
and according to the newnes book you can either use a 3OP19 (Mazda) or a PL36 (Mullard)

Lee
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Old 13th Jun 2006, 6:44 pm   #6
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Righto, Matey.

First of all read up an TV basics. www.oldtellys.co.uk

If a set has had previous attention, check the obvious things first. Including valve types and positions. As the site above says, it's all to easy to be caught out!

Have you got a meter? Up to 1000v should do, and since it's your first set, don't poke it round the Line Output stage.... Killing the Line Transformer is one thing, killing YOU is something we can't fix.

That PL36/30P19 is the line output valve by the way. If there was a valve missing then none would light, so I'll assume you've fitted a PCL85/PCL805. They're the same valve by the way. If you've put something else in there, switch off immediately, remove it, pray, slap your hand and take up that offer of a PCL85 on here.

The HT is through that dropper resistor, by the way. The valve section of it is OK but the HT section needs checking. First check the 1A Delay Fuse. If it blows and If a replacement blows, come back here. Then check R169 (7 Ohms) , R165 (13 Ohms), D10 (BY100), R168 (75 Ohms) and R167 (75 Ohms).

You then may not get vision, but should get sound. If not, work the system switch back and forth if you havent done already, and leave it on 625 lines.

If you haven't got the manual, say so now and somebody will post it. I've tried... can somebody PM about this please?

Cheers,

Steve P
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Old 15th Jun 2006, 9:45 pm   #7
Zelandeth
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Well, I've been poking around a bit more with it today, having managed to bodge together a temporary resistor, and admit to having found no additional signs of life after bridging the O/C section in the dropper somewhat offputting. Also initially tried resoldering one connection there which was hanging on by one strand of heavily oxidised copper. Soon gave up (soldering to rust, interesting challenge!), and cleaned the terminal up, and put on a spade connector from my automotive bits box. Much better.

Set is presently drawing 72W of power - starting out at 81W before dropping off.

One interesting habit I've noticed, is that when the system switch is set to 625, after a minute or so, the panel lamps start flickering, before eventually going out - the tube heaters don't however. So much for my theory of them being in series! Wondering if something as simple as a duff thermistor might be responsible for that behaviour.

No definite signs of life from the line side of things yet - though I think there may be life in there yet, there's a very, very faint "ringing" noise coming from somewhere in the general vicinity of the LOPT - I'm not sticking my ear close enough to it though to verify that! Sounds as though it might be trying though.

Spotted my first dodgy capacitor too, by the layout diagram (Thanks Dave!), looks as though it's C83. (Electrolytic, blue can, middle of chassis directly under the CRT neck), little sucker's leaking. Of course, it's decided to be in a real pig of a location...Actually taking the chassis out is starting to sound like a more attractive option every second here. Only question is really with the anode connection to the CRT, it ain't very long, I've no idea whether it can be disconnected (though no doubt, someone will tell me), and I don't want to go pulling things.

Just keeping my fingers crossed I don't need to start hunting for an LOPT at the moment! A little ways off being able to tell yet though.

One thing I've not checked yet - because I haven't been able to find it: A 1A delay fuse, where on earth is it? Can't see it on the circuit diagram or component layout...

Last edited by Zelandeth; 15th Jun 2006 at 9:58 pm.
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Old 15th Jun 2006, 10:03 pm   #8
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Quote:
Originally Posted by Zelandeth
Only question is really with the anode connection to the CRT, it ain't very long, I've no idea whether it can be disconnected (though no doubt, someone will tell me), and I don't want to go pulling things.
IF it's like a modern telly, you go about it like this...

First, discharge the tube and LOPT by sliding a screwdriver under the rubber cap until you feel it touching the central metal terminal. Then use another screwdriver blade to link it to the aquadag (graphite) coating on the tube. Beware that there may be quite a big "pop" and flash, and obviously, use drivers with well-insulated handles.

Then, gently peel back the rubber cap - you should be able to see the terminal. The terminal can be disengaged from the tube by sliding everything to one side, and tilting the cap so that one of the "claws" is lifted out of the cavity. Then slide it the other way, and the other claw should disengage.

Easy to do, difficult to describe, so here's a (terrible) sketch of a cross section through the tube bowl and the connector
(Thanks for the MS Paint tip-off, Adi).

Nick.
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Old 16th Jun 2006, 9:13 pm   #9
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Quote:
Originally Posted by Zelandeth

One thing I've not checked yet - because I haven't been able to find it: A 1A delay fuse, where on earth is it? Can't see it on the circuit diagram or component layout...
On the VC53 chassis the only fuse was on the switched side of the mains input (like most other mono sets of this era) so it depends on how it has blown, if it has blown gently ir could be due to a surge or line output stage fault. If it has blown violently then it is normally due to the modulation cap or HT rectifier diode.
On the VC53 the mains fuse was located by the mains dropper resister but it's location may well vary on the other chassis variants. It should n't be difficult to trace it though.
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Old 16th Jun 2006, 10:27 pm   #10
Zelandeth
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Well now...would you look at that...an 800mA delay fuse...in the pencil pot on my desk...Slightly low...but if it blows it blows...can't hurt to try. Clipped myself in a somewhat more suitable resistor (discovered a jar of them in the loft when hunting fuses!) in place of the break in the dropper (0.5 ohms too high, but for the purposes of very, very preliminary testing, it'll do, set's only going to be running for seconds at a time). Then applied power, and crossed fingers.

An impressive display of sparks from the crocodile clips holding on the wires to my resistor on the dropper itself...Nothing for a few seconds...then...I have sound - lots of it! Power is briefly removed, so that I can turn the volume down. This operation of course requiring a screwdriver as the power/volume knob is not actually attached to the control.

Take two...I have sound again (albeit slightly more amenable levels of it)...and a very distinct line output whistle, quite healthy sounding actually. No image though. Until it occurred to me to tweak the brightness control...and yes!

http://zelandeth.artamir.org/compute...ns_of_life.jpg

Sure, I have frame collapse...but given that the height pot's bust, that's hardly surprising. Just before removing power, I did poke that with a well insulated screwdriver, and I did get a nearly full screen blank raster.

Including getting the photo there, I've had it running for less than a minute - and that's the last time it'll be seeing power until I've got a proper resistor soldered in place (though given this 5W one got only moderately warm, guess my 11W choice might prove slightly OTT! Granted, this was only seeing power for about 25 seconds a shot!), and have a proper 1A fuse on hand for when this 800mA one blows, which it inevitably will!

It's aliiiive....sick, but alive!

I know now at least, that it IS worth pursuing further. The LOPT obviously works (at least when cold), and the tube's servicable. Time to get down to business properly now...This old thing will show images again yet...
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Old 17th Jun 2006, 10:14 pm   #11
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Hello,
The K.B. [I.T.T.] chassis from the first dual stamdard VC1 to the last VC52 were of the very best liked both by the customers and the guys that had to repair them. There are very few stock faults and the capacitors used are of good quality on the whole.
I sold large numbers of them and kept a couple of the old soldiers when their customers decided to buy a colour set to replace them.
The picture was taken this evening from the screen of an RGD fitted with the VC1 chassis. This was the first dual standard chassis using an ECC81 as line oscillator and two line hold controls, one for 405 and one for 625. This receiver has not been switched on for around 8 years and came straight on as you see. The UHF tuner is valved and the CRT is an early bonded screen type. Even under photo flash conditions the picture is still bright enough to stand out undiluted! The cabinet control cloth is scruffy unfortunately.
The later set is a K.B. fitted with the VC4 chassis This uses the PCF802 in the line oscillator stage and a single line hold control. The UHF tuner is a much improved transistor type. Both very fine receivers. The 'DEEP SCENE' followed on from the VC4 but was a limited market and was just one model from a large range of sets fitted with the VC51 chassis. Regards John.
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Old 19th Jun 2006, 10:48 am   #12
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Default Re: Kolster Brandes KV024 (VC51 chassis)

The VC1 and VC2 models have a three way tag panel to allow the connection of a small transistor amplifier which can be used as a baby alarm.
An isolation transformer is fitted between the input socket and the transistor amplifier for safety.
The output from the amplifier is connected directly to the grid of the audio amplifier valve.

Another difference between the VC1 and the later models is that the VC1 employs two 6BW7 pentodes in the sound IF amplifier and only one is used in the VC2/3/4/5 sets.
Also, the sound output valve in the VC1 is a PCL82, the others use a PCL86.

DFWB.
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Old 23rd Jun 2006, 11:42 am   #13
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Right...er....yeah. This could well be the lopt, and if anyone's got one please get it up here!! In the meantime....

Check that the sockets and wiring of the PL36 and PY800 are OK.
Check that there is power to the PY800. On this valve it's the pin underneath.
Check that there is a negative voltage on the Control Grid of the PL36. If not, have a look at the Line Oscillator (V12 - PCF802) and round there. Especially if the PL36 is glowing cherry red!
Check that there is a DC Voltage on the Screen Grid. Check R161 (I think - small diagram) and the switch above it (part of the System Switch). Also check the Brightness Control for NO VOLTS.
Check again that solder job on the LOPT. You never know whether its OK. Does it actually connect with the LOPT.
Put an Ohmeter across Pin 14 and the other pins of the LOPT.

Cheers,

Steve P
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Old 23rd Jun 2006, 3:30 pm   #14
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Sorry! Mental Abberation. It's pin D of the LOPT!
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Old 23rd Jun 2006, 8:55 pm   #15
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Default Re: Kolster Brandes KV024 (VC51 chassis)

First off, number on the sticker on the LOPT: 39/LO/62 ZA3.

First checks.

Impedance of LOPT connections, from pin D (in ohms, obviously).

A: 2.9.
B: 13.5.
C: 14.4.
E: 12.0.
F: 10.5.
G: 13.0 (and extremely hard to get to!).

Of to check the wiring and such as mentioned above now. My connection I have checked, and is perfect. That was my first thought!
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Old 24th Jun 2006, 12:50 am   #16
Zelandeth
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Default Re: Kolster Brandes KV024 (VC51 chassis)

PL36 (or 30P19 at this point in time) control grid (g1) voltage: -77.6V. G2 is sitting at around 65mV.

...and why hello there...what I believe to be R161 is reading as open circuit...hmmm....Let's replace that...

EDIT: That's actually R141...but it's still open circuit! R161 appears intact.

Last edited by Zelandeth; 24th Jun 2006 at 1:00 am.
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Old 29th Jun 2006, 7:35 pm   #17
Zelandeth
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Default Re: Kolster Brandes KV024 (VC51 chassis)

Well, sticking a new resistor in place of R141 I am glad to report has restored EHT with the old 30P19 in place.

Now, question...which is probably a really stupid one...but I'll ask anyway.

Before going to disconnect the 30P19, is it necessary to discharge the CRT?

If I don't get an answer, I'll go ahead and play it safe anyway...I just hate discharging the darn thing! There's something about large sparks and loud cracks that's just unnerving...
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