How to improve picture brightness on Compaq 472p?

September 27, 2018 at 02:35:53
Specs: Linux x86_64
Hi I am looking for all info about Compaq 472P CRT monitor- service manuals, user manuals and if it is a problem with flyback transformer. The picture is dark on monitor, which make playing PS4 games very hard. Does the change of flyback transformer would improve it? Is the HR7937 correct replacement for flyback transformer for this monitor? What is the maximum resolution of monitor? Of course I used the knobs of the Brightness to maximum level.

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#1
September 27, 2018 at 04:55:59
How old is this monitor?

Being a crt it is likely that the cathode emitter (the bit at the back end of the tube neck and which emits electrons which impact on the phosphor at the front) is becoming "worn out". i.e. it's a case of low emission

All crt display suffer from this effect in time; and similarly even the phosphor can fail to produce the same brightness as when new.

In the "olde" days one could replace an ageing crt tube with a crt which has had a new gun installed, been replaced; and the phosphor coating being left as was. The quality of the picture would be better than it was at time of replacement; but not as good as if a new crt tube. One could also get crt tubes which had been recoated - a new phosphor coating applied; but they were less common.

A tube with only one of those remedies applied would last a reasonable time; but would never be as good an image as true new straight from the factory tube.

Ad if one sought to have both remedies applied it was likely cheaper and easier to get new tube!

Generally it was in the black 'n white days that one replaced the cathode emitter, and possibly recoated the tube face; but less common with colour displays.

So replacing the flyback transformer is not likely to help. When that goes down, or starts to fail (and they can in effect leak depending on style of the transformer) one gets either an over large display, or ballooning of display dependant on picture content.

When the cathode goes into low emitter state one will inevitably start to crank up the brightness to maximum, and at some stage start to see fly backlines on the display; and also contrast will become significantly less...

So rather than spending money of this crt display, invest on a new display? Sad to say that the olde crt system has had its day; as getting replacement tubes is well nigh impossible (unless willing to pay price). For me the colour imagery of a good crt was preferable to any led, oled etc; and far less inclined to cause eye strain. Most (all???) oled/led display come out the box with colour temperature settings way too high; over contrasted, over bright; and frequently over chroma'd (too much colour applied).

The human eye is not happy with persistent exposure to colour temperatures in excess of 6000K, preferring to be around the 4500K at most. Likewise lighting around 2700/3000K is fine but sadly many led light sources are way above that; and cause eye strain in due time.

message edited by trvlr


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#2
September 27, 2018 at 05:35:51
sorry i tend to not read everything....but:

Just buy a 2nd hand 1080p monitor or old TV, really 50$ or less and you're set.

I mean you can try to figure out how to improve your old monitor, on what 5+ hours plus extra costs. or just go to work for 2 hours and pay for a new one.

You save 3+ hours and you get a better monitor.

i5-6600K[delid]@4.8GHz/4.3GHz@1.4v LLC=6 | 2x4GB Crucial-DDR4-2133CL15@14-14-14-28 1T 2700MHz@1.35v
MSI Armor RX 570 4GB@1340Mhz core@1.110v/1865MHz BiosModded


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#3
September 27, 2018 at 09:48:43
I posted a slightly lengthy response (my #1) for the benefit of those too young to remember the good olde days of b 'n w television. And why the picture over time would lack contrast, go dim - requiring the brightness control to be increased over time; and how it could be resolved - on occasion.

Having serviced/repaired both domestic and broadcast crt displays, a low emission cathode was not at all uncommon. Regunning (as we used to call it when a crt had the whole filament and cathode assembly replaced) was not common in broadcast environments; but very common for domestic (much cheaper to end user than a new tube; and allowed an ageing phosphor to continue in use for a year or three more). Low emission crts were sent the crt to a suitable regunning facility, and they did the job and put the renovated crt back on the market as such.

later on colour crts could also be done but invariably that was the broadcast environment when a given spec'd crt was no-longer available as new for an otherwise still viable and useful colour monitor. Problem was that they were never as good as a new crt - the rgb phosphors having also aged... But they did work within reason.


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#4
September 27, 2018 at 14:32:52
It's not even a good CRT monitor. 14" SVGA from 1994, 800x600 resolution. IMO, a complete waste of time & effort.

http://www.retrocomputing.net/parts...


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