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Old 16th Dec 2019, 10:00 pm   #41
julie_m
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Default Re: Philips G8 G22K522

You connect a bench power supply to one of the windings of the transformer, and adjust the voltage and current so it dissipates a few watts (remember, power = voltage * current, if your PSU isn't a fancy one with power on the display). It then dries itself out from the inside. With DC, nothing will happen on the other windings, so they may be left safely not connected to anything. This would not be the case, if you used an AC supply.
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Old 17th Dec 2019, 3:05 pm   #42
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Default Re: Philips G8 G22K522

As you say this TV has been in use till fairly recently and then kept dry, I think your method of keeping it warm will do the trick. These transformers did fail all the time, but not usually due to damp.
Unless you have a regulated bench PSU with current limiting, then I'd leave well alone.
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Old 17th Dec 2019, 4:03 pm   #43
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Default Re: Philips G8 G22K522

Hi,

Thanks for letting me know, Julie, unfortunately I don't have a bench PSU, so as Welsh Anorak says, I'm going to leave well alone for now.

When I get the caps replaced, and it's time to power the whole set, I'll keep it in front of the radiator for an hour or so just to make sure it's dried out, before applying power.

Thanks for your help
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Old 17th Dec 2019, 9:18 pm   #44
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Default Re: Philips G8 G22K522

A hair dryer can be useful for drying out sets.
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Old 17th Dec 2019, 11:12 pm   #45
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Default Re: Philips G8 G22K522

Great idea, i'll keep that in mind when the time comes.

Thanks
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Old 13th Jan 2020, 9:45 pm   #46
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Default Re: Philips G8 G22K522

Hi, so I have finally managed to replace the capacitors.

Is it safe to turn reconnect everything and turn on, and see what the result is, or should there be anything else to do before turning on?

Thanks
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Old 13th Jan 2020, 11:37 pm   #47
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Default Re: Philips G8 G22K522

Perhaps wind the HT down at first and see what the result is. If all is well, then correctly set up for 205V although I always set it between 195Vand 200V conducive with sufficient width. Less strain on everything with the slightly lower HT.
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Old 14th Jan 2020, 12:27 am   #48
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Default Re: Philips G8 G22K522

Not too scary. at least it uses a thyristor psu as opposed to a SMPS, but yes, the line transformers did suffer, at least its not a G11!
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Old 14th Jan 2020, 9:26 am   #49
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Default Re: Philips G8 G22K522

Quote:
Originally Posted by Tazman1966 View Post
Perhaps wind the HT down at first and see what the result is. If all is well, then correctly set up for 205V although I always set it between 195Vand 200V conducive with sufficient width. Less strain on everything with the slightly lower HT.
How would I go about winding it down? Is it like a simple pot adjustment or the like, or something with a few more steps? I’ll be happy to do it of course.

Sorry if thats a bit of a simple question.

Quote:
Originally Posted by toshiba tony View Post
at least its not a G11!
And from the stories I’ve read, I’m glad!

Thanks for your help
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Old 14th Jan 2020, 12:44 pm   #50
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Default Re: Philips G8 G22K522

R1370 is the set HT pot with the voltage measurable at the 800mA fuse FS1391. The other pot is the overvoltage protection adjustment.
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Old 14th Jan 2020, 2:00 pm   #51
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Default Re: Philips G8 G22K522

Further to what has been said above . The set HT control is on the left hand side power supply panel almost in the middle near the white plug. from memory I think the overvoltage protection control usually has a red cover over it.
It may be a good idea to put a little switch cleaner on the tracks with the power off and work the controls back and forth to clean them first, then set the HT control to minimum and the overvolts control midway before switching on.
Just in case the HT control is scratchy and intermittent you don't want the HT leaping up and down!
Rich.
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Old 14th Jan 2020, 5:48 pm   #52
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Default Re: Philips G8 G22K522

Thanks for clearing that up,

I'll get some cleaner and get to doing that.

I'll let you know how it goes.

Thanks for your help
'77
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Old 14th Jan 2020, 7:01 pm   #53
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Default Re: Philips G8 G22K522

Hi there.
I have quite a few spares if you require anything please send a PM, best of luck!!
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Old 14th Jan 2020, 7:24 pm   #54
19Seventy7
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Default Re: Philips G8 G22K522

Hi,

That's a really kind offer, i'll let you know if im in need of anything.

Thank you, it's really appreciated
'77
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Old 16th Jan 2020, 9:19 pm   #55
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Default Re: Philips G8 G22K522

Hi,

I've cleaned and adjusted the pots recommended, and switched the set on.

I have sound, which drops in volume occasionally, but a tap to the side of the set brings it back temporarily, but taps sort that out.
There's also what I'd believe to be low EHT, I can hear a faint line whistle, but there's no form of picture on screen, even with full brightness, not even with lights off, until switch off, and a small red line appears, morphing into a dot then disappearing.

Perhaps if there is low EHT, that could be due to the tripler, hence it left hanging?

Thanks
'77

Last edited by 19Seventy7; 16th Jan 2020 at 9:20 pm. Reason: Extra Information
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Old 16th Jan 2020, 10:31 pm   #56
slidertogrid
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Default Re: Philips G8 G22K522

Quote:
Originally Posted by Tazman1966 View Post
R1370 is the set HT pot with the voltage measurable at the 800mA fuse FS1391. The other pot is the overvoltage protection adjustment.
Connect a voltmeter between chassis and the fuse and see what the H.T voltage is. Adjust the set h.t pot for 200 volts in the first instance and see if that makes any difference.
Rich
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Old 16th Jan 2020, 11:23 pm   #57
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Default Re: Philips G8 G22K522

I've just returned the pots to their original positions, and retested, as I haven't been able to find an isolation transformer yet, that I can afford, I haven't tested the voltage. (I don't think this is an isolated chassis?)

I do now get a raster, albeit very red and dim, it's not a solid raster. There's no blue or green, and I've checked behind the speaker grille to make sure all guns are on, which they are.

I was wondering, would it be safe, to switch the leads round on the chrominance panel to the red pin, to see if I get a different coloured raster, eliminating the idea of a dead CRT. I'd have thought it to be safe, but I'd rather not risk it yet. I don't have a tester, either.

Thanks
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Old 17th Jan 2020, 12:55 am   #58
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Default Re: Philips G8 G22K522

First light

Measure the HT on the 800mA fuse and make sure it's under 200V.

Swapping the drives to the tube guns around is a normal diagnostic practice.

Yes, the G8 is a live chassis set!

If I recall correctly, the red green and blue A1 controls are at the bottom of the convergence panel at the front of the set behind the speaker grille. They work like individual brightness controls,
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Old 17th Jan 2020, 2:54 am   #59
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Default Re: Philips G8 G22K522

I was glad to see something on screen, even if it does have its issues.

Would it be safe to measure without a isolation transformer if i attach and detach the meter while the set is off and not touch the set while it is on.

I’ll get to swapping the colours over tomorrow, fingers crossed.

Are there two different controls for the guns on the convergence panel? There’s three at the bottom, which are just simple push button, which I figured turns the guns off or on, no different brightnesses. I haven’t looked around in there much, apart from the on/off buttons.

Thanks for your help
‘77
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Old 17th Jan 2020, 5:43 pm   #60
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Default Re: Philips G8 G22K522

Just a quick update, i swapped the blue and red gun drives over, turned on the set to be given this on screen - MUCH better than the results i were getting before.

Thanks
77
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