Old old monitor

**Very risky. The thing may use a SMPS. It will certainly use an LOPT driven by a high frequency oscillator, which may or may not start, when gradually ramped up. You may end up causing more damage. Or not. It's a crap shoot IMO.

Trevor Wilson

Agreed. Just apply normal power. At least you'll know pretty quickly if something's going to blow up. :( :)

It may be OK if it wasn't used over that time and was stored in a cool place.

To be doubly sure, you could check the ESR of electrolytic caps in the power supply and deflection, and/or simply replace the main filter caps.

How important is it to get the monitor going?

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Also, some old PC monitors rely on receiving sync from the computer's video adaptor before generating EHT etc. Running at a reduced supply will most likely not allow the interface circuitry to function to allow sync through.

--
Adrian C

Hi!

I think it might be OK to just plug it in, turn it on and go. I've done exactly that with a number of old monitors that had been sitting for a long time and had no problems. The overwhelming majority of "duds" were a result of picture tubes that had simply been "used up" before the monitor was taken out of service. I don't remember any offhand that died upon power-on.

As has been mentioned, some monitors have switch mode power supplies. These may be stressed by low line voltage and they could fail either immediately or after running for a while.

William

If it isn't vacuum-tube (valve) based, it really isn't ancient, and even then if it dates from the late '60s or newer it really isn't ancient ;-).

Why would you worry about applying power to a 20 year-old monitor? For

*od's sake, that would have only have been 1987. A soft start using a ferro-resonant isolation transformer or perhaps a continuous-duty UPS would prevent transient or large inrush problems but I really wouldn't worry too much ;-)

OTOH, if it has a round CRT and uses a 6BQ6 sweep tube, I'd use a variac.

Regards,

Michael

On 06 Nov 2007 19:08:37 -0500 in sci.electronics.repair, Sam Goldwasser wrote,

OK, that's what I will do.

If it works I can get rid of an even older monitor; that one's a Ball with a steel box 22"x20"x20" weighs probably 100lbs (I barely lift it) and has airline arrivals and departures burned in to the phosphor.

>

Just plug it in. If it were 50 years old I'd say use a variac, but 20 years is not that long, the components will be relatively modern.

connect a light globe in the active lead of a power lead and then switch it on. This technique is useful when repairing/testing monitors.

Andrew

I recall using ones like that. They were really nice monitors. :)

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"msg" wrote

Dust could be a problem around the EHT.

How do I know this?

I know this because just this last Saturday, I lost a 21" Iiyama monitor that I paid about 650 GBP for about 6 years ago.

I'd known it'd been on its way out for months because sometimes it would spark over inside and the picture would change to a bright vertical line in the centre. I assumed it was caused by dust around the EHT. I'd switch it off, wait for a few seconds, back on again, and it'd usually be ok.

Of course this sparking chars the dust and leaves conductive carbon around the EHT area.

On Saturday morning, what I knew was gonna happen happened. I switched it on, and there was a *poooufff* - not that loud - but unlike anything I'd heard it do before.

Lights out - forever.

Martin - I'm not bitter, Sassnfrassnsonofabitchstoopiddogshitgoddamnmofo....

--
M.A.Poyser                                                  Tel.: 07967 110890
Manchester, U.K.          http://www.livejournal.com/userinfo.bml?user=fleetie

Dust didn't do that, a cracked solder joint in the horizontal deflection area did. The obvious clue is the lack of deflection when it acted up. 5 minutes with a soldering iron *before* the HOT and possibly other components blew would have saved your monitor.

that just shows why you shouldn't nurse intermittent faults like that along. by the way this is nothing to do with dust, it is a bad solder joint. In carrying on using it you have stressed the scan circuits and finally they gave up the ghost..... A waste of a good repairable monitor. hope that serves as a lesson to you.... -B

By the way, it worked fine.

I've had two Iiyama monitors with that fault. Just needed to get underneath the main circuit board and resolder the connectors to the scan coils.