OT: Strange computer monitor problem

[Jonno]

Brian Gaff scribbled

Were you using standby with a wireless mouse/keyboard. It's a common error.

[The Natural Philosopher]

VGA only has various RGB signals and a H sync and V sync.

Presumably the monitor detects the presence or absence of one of the sync signals.

So one test might be to unplug the VGA lead and plug it in again.

Oh, a dim memory from years back ...maybe the VGA is actually loose and until it warms up it is not making proper connections?

As per usual binary chop,. Does the computer work on anther monitor? Does the monitor work on another computer?

[Harry Bloomfield]

Roger Mills laid this down on his screen :

It sounds as if the switch mode power supply of the monitor is failing to fire up, probably a failing capacitor in the power supply.

[Dave Plowman (News)]

All the VGA monitors I've had will still show an off-on light if switched on with no connection. The warning light may well change colour with no signal, though.

[Roger Mills]

Indeed. I left the monitor on standby last night - connected to a wall socket rather than the smart switch, so that its power didn't go off when the computer shut down. [In this state, with power on but no video signal, the green power light flashes rather than being solid.]

This morning, when we turned the computer on, the monitor came to life immediately. So the monitor's power supply's cold start arrangement has to be prime suspect.

We'll probably live with it until it dies completely. It doesn't owe us a lot - it's over 14 years old. I don't really fancy trying to mend it myself, and the cost of paying someone to fix it would probably approach the cost of a new one.

[I found out its age by checking my financial system for evidence of the purchase, and was horrified to find that back in 2001 it cost us nearly 600 quid for a 17" 4:3 monitor! By comparison, I have recently bought a 24" widescreen monitor for only just over £100.]

[Dave Plowman (News)]

A flashing light or colour change is what I'd expect with no signal.

Or your 'posh' dizzy board ain't supplying the full 240v or whatever. It will likely have a solid state 'switch' somewhere, and they ain't loss less.

[T i m]

OOI, have you ever done any PCB type soldering? Would you *like* to carry on using it by fixing it yourself? (If you could wave a magic wand etc (and this is a diy n/g after all))? ;-)

Depending on who that 'person' was of course?

See, there are people out there that actually have such skills that mean that sort of job is really bread_and_butter to them and given the right caps 'in stock' I'm sure that there are some here who would do the job in a few minutes and for a cuppa. ;-)

I've done quite a few now, TV's and monitors and not including those with external PSUs.

Typical process. Half a dozen screws and possibly some clips round the outside (popped open by a strong thumbnail) and the back comes off. Often the PSU is a small stand-alone module and it would be fairly easy to spot if the caps by the bulging or even split ends.

Then it's 'just' (easy for me to say I know, with my 40+ years experience as a electronics / field support 'tech' and desoldering station) a matter of getting under the board , desoldering the caps (often one_at_a_time to avoid confusion, marking the new ones as you go) and soldering the new ones in.

Re-assembly is the reverse of disassembly, as it says in the Haynes manuals.

It probably took me longer to type than it would take to do. ;-)

And assuming that is the problem, it should be good for a good few years.

So, lets say it works and you have just saved say 60+ quid on a new one. Now you have done the one, you might / should also be able to do the next and so on, potentially saving 'lots'.

Not suggesting *you* should, just suggesting it can be easy, moneysaving and satisfying and in many cases you have little to lose.

(You do need to be careful and YMMV of course).

Cheers, T i m

[The Natural Philosopher]

That used to be my thinking till I compared actual power consumption and realised a new PC or monitor would pay for itself in less than 2 years down to better standby and operating power

[Mike Tomlinson]

En el artículo , Broadback escribió:

The "some time before it is usable" is a dead giveaway. It'll be the capacitors.

The failing capacitors affect the power supply voltages fed to the circuitry, usually making them too low for it to operate properly; the effect can be unpredictable. Odd symptoms like the one you describe are very typical.

[Roger Mills]

No, if it had been that, it would have worked when I first connected it to a wall socket rather than the smart switch yesterday. It didn't! I used two separate power leads (one at a time!) one connected to the smart switch and the other to a wall socket. I measured the voltage of both with my digital multi-meter - and they both the same (~238v IIRC).

[Roger Mills]

Thanks for the encouragement. I *might* have a go when I run out of better things to do. Meanwhile, I've replaced it with a 19" 4:3 monitor which I "retired" when I bought a wide-screen monitor for my computer. It's actually newer than the problem one, and slightly larger and - in my opinion - has a much better picture. I'm hoping that SWMBO will agree when she sees it!

[News]

In message , Roger Mills writes

I paid six hundred quid, I think, for my first new, proper PC, an Elonex 386 a long time ago, and the price for each improved replacement has only ever gone down.

[Adrian]

Is that all?

I remember, as a student in the very late '80s, pricing up a PC - an Elonex 386SX - to no great spec, even at the time... Not going to happen under a grand and a half.

The utter jaw-dropping value a year or so later of an HP Deskjet (Colour? Don't be daft!) suddenly being under £500...

[News]

Indeed. It was a 'private sale' new, unused PC, hence the price, which had to be cash. Perhaps I should have asked more questions but given that I was in no position to buy a brand new PC from a shop, didn't.

Needless to say it is still in the loft, complete with original boxes, manuals etc.

[T i m]

I think I paid (only) £360 for my HPDJ500c when the RRP was also around £500. Handy knowing someone who worked at HP. ;-)

Now a cheapo inkjet printer is often cheaper than it's replacement cartridges.

I found the receipts for my first VGA card, Adaptec (ISA) SCSI controller and 80Mb SCSI hard drive the other day .

Cheers, T i m

p.s. Is it 'sad' when you know (or knew) what bus (8/16b ISA, ISA/LB EISA, MCA or PCI etc) is used on an Adaptec controller from it's number?

[The Natural Philosopher]

Oh I got a V70 (?) clone with an orange monitor for around £600 IIRC and a hard drive too. Must have been around 1985

[Alan Dawes]

I'd agree particularly as Roger told us in his post yesterday "It doesn't owe us a lot - it's over 14 years old" so it would have been constructed at the height of the "Capacitor Plague" where from 1997-2007 large numbers were made with a cheaper formulation of electrolyte which reduced the life and caused capacitor rot.

I've experienced this in 2 PSUs in computers (the first caused the heads in 3 hard drives - main and 2 backups - to burn out - data recovery cost £450) and one in a Topfield PVR where I had to replace 7 capacitors in the PSU.

Alan

[T i m]

I've done that on all 3 of our Topfield 5800's. ;-)

Cheers, T i m

[bert]

I;ve recently had a similar problem (Viewsonic monitor) and came tot eh same conclusion. Bought a replacement.

[bert]

In article , News writes

The first PCs were priced at about £4k because that was the all-in cost of the alternative which was a terminal on a mainframe.