Monitor Chassis swapping? Should it work ok not?

[DarthNuno]

...that the question! 

Ok, in one hand I got this complete but non working chassis for WG K9100 model 






...and on the other hand I got this complete and supposed working chassis for an Electrohome G07 model 



As you can see, the 'shape' and the number of connection for the tube looks identical.

So my question is : Can I use my Electrohome G07 chassis with the tube originally used for the WG K9100? Why it doesn't work finally? The tube for both chassis are the same size, a tube is supposed to be 'passive'? Both chassis are from the same era, ... so finally why it doesn't work?

What do you think about this?

[level42]

I don't completely understand your posting, do you mean you already tried it and it doesn't work, or are you just informing before you try ?


The main issue is the yoke impedance.

If it's "about" the same, this should indeed work, at least in theory.


The yoke coils are either "low" or "high" impedance. You cannot use a chassis that expects "low" impedance on a "high" one and vice-versa.

Measure the yoke coils (both horizontal and vertical) and note the resistance values. This should give an idea.

[DarthNuno]

I don't completely understand your posting, do you mean you already tried it and it doesn't work, or are you just informing before you try ?

I'm asking before to try 

Measure the yoke coils (both horizontal and vertical) and note the resistance values. This should give an idea.

Where to get the measures? it's on the back of the tube itself, between two of these 10 pins that coming out on the tube?

[level42]

There is a 4 wire connector that goes from the yoke /neck to the PCB. Measure there.

Here's a some info and pics:

http://www.therealbobroberts.net/yoke.html

[DarthNuno]

Thanks André, I'll check that.

[baritonomarchetto]

I dont remember where, but i read that sometimes also the pinout on the neck PCB is different even if the connectors looks identical, so pay attention to this

[DarthNuno]

OK, here the entire WG 19K4605 non working :



The 4 wires coming from the yoke 



...directly connected to the (non working) board...



...so I have to cut them. Here's the situation now 



1. The two black wires on the left are used for the degauss. I presume this connector will have to be plugged on pin 11/12 on the Electrohome chassis?
2. The red, green, blue and yellows wires are coming from the yoke, and I'll have to do a connector in order to plug them like this? 



3. The last one (the black on the right) is a ground to be plugged on the neck board.

Doesn't looks difficult but...not sure I'll go further than this, I may use this Electrohome 'refurbished' chassis ... to replace an other Electrohome G07 chassis after all  In addition, the tube I planned to use for this 'experience' has some serious screen burns...

To be honest, I got this 'Monitor Chassis swapping' when I saw this on ebay 



This is a fixed price listing for a single, new in the box, Entech 150020 CGA CRT Monitor Chassis.
 
This item is supplied new and in original factory packaging
 
These units should only be exchanged or fitted by a qualified service engineer
 
Technical Features:
 
Power Input: 96-240VAC Free Voltage (Power Consumption <60W)
Input Signal: RGB Comp Synch GND (Colours Max 5V P-P) (Synch 2-4V Neg Edge)
Focus:  Electrostatic
Convergence: Self Convergence
Deflection Yoke Match: LH - 1.92mH  LV - 30mH  RH - 2.0 Ohm  RV 13.5 Ohm
H Synch: POLARITY 1Vp-p ~ 5Vp-p : FREQUENCY: 15.75 KHZ : PLUSE LENGTH: 3us ~ 7us
V Synch: FREQUENCY: 48HZ ~ 55HZ : PLUSE LENGTH: 190us ~ 500us
Tube size: 48cms/ 20"
 
On Board Controls: B+, Focus, Screen, RGB Gain, Width
Remote Controls: Power, H Hold, V Hold, H Position, V Position, Brightness, V Size, V Freq
 
Kit Contents:
 
Main PCB Chassis Assy (Neckboard fitted and connected)
Remote Control PCB - fitted and connected
Degauss Coil
Earthing Braid
Video Input Cable and Connector
Deflection Yoke Cable and Connector
CRT Safety Manual
 
Please note that the DY on your tube should be matched to this chassis type. If you need to check your CRT DY readings then a suitable LCR multimeter is available for purchase in my ebay shop, in the tools section.
 
Please note that due to the nature of these items, warranty repairs cannot be carried out on parts that are damaged due to customer installation errors - you must have a fully working tube with a suitable Deflection Yoke for this item.
 
Note - Identification of CRT size
 
There will be a sticker on the rear of your CRT tube itself - usually containing the manufacturer data. There will be a long alphanumeric code which gives data on the tube; this code will begin with an A for standard dot pitch tubes and M for higher resolution tubes. There will be 2 numbers immediately following this letter, and these numbers represent the size of the tube in cms.
 
eg:  A51EAG001X01 - this shows that it is a standard dot pitch tube with a 51cms diagonal screen.

If you need any additional info on this then please e-mail for details - International buyers welcome and I have good discount rates with Parcelforce/GLS.

Shipping weight is 2.5 kgs, which means that normal royal mail is more expensive than parcelforce - multiple purchase customers should wait for a checkout invoice to be raised as I can ship up to 30kgs in one carton with parcelforce for the same flat rate

 A full range of CRTs, Chassis, and complete monitor assemblies is now available in the ebay shop - take a look - in addition there are also specialist video converter units for industrial CRT replacements where it is necessary to use a standard LCD monitor as a replacement





What do you think about this? May be a good option to give a second life to our monitors/tubes?
Something strange on the description : V Synch: FREQUENCY: 48HZ ~ 55HZ : PLUSE LENGTH: 190us ~ 500us
Should it be 60HZ instead?

[italiandoh]

What do you think about this? May be a good option to give a second life to our monitors/tubes?

Well, why not ? The specs are typical of a standard 15 Khz CRT monitor.

Something strange on the description : V Synch: FREQUENCY: 48HZ ~ 55HZ : PLUSE LENGTH: 190us ~ 500us
Should it be 60HZ instead?

It is correct. The spec is about the adjustable vertical synch rate (via pot on chassis remote control). Of course PLUSE is a grammar error and should be PULSE. 50 or 60 Hz is the picture refresh rate which is a different thing.

Matteo

[DarthNuno]

Something strange on the description : V Synch: FREQUENCY: 48HZ ~ 55HZ
Should it be 60HZ instead?

It is correct. The spec is about the adjustable vertical synch rate (via pot on chassis remote control)...
Matteo

So this particular model for sale on ebay wouldn't work because it doesn't deliver 60HZ vertical synch rate but only a maximum of 55HZ... and then, useless for our 60HZ boards?

[italiandoh]

So this particular model for sale on ebay wouldn't work because it doesn't deliver 60HZ vertical synch rate but only a maximum of 55HZ... and then, useless for our 60HZ boards?

Bruno, you're confusing the picture refresh rate http://en.wikipedia.org/wiki/Refresh_rate with the vertical synchronization http://en.wikipedia.org/wiki/Vertical_synchronization. This monitor will work with 60 Hz games if the game's resolution will be low enough (i.e. 80s games are mostly OK).

Matteo

[DarthNuno]

OK thanks Matteo 

[DarthNuno]

...and back on this!

I had this box since 5 years! 



It's time to give a try...



...to this brand new 20" CRT Free Voltage Monitor Chassis Entech 15020 CGA.

I have here two tubes that should be compatible with that chassis, which is basically supposed to work with almost all 20"CRT in arcade CGA monitor tubes :

- HITACHI 510UJB22 :



- ELECTROHOME? / 19VMNP22 / 17-7198-12 :



So I tried that chassis with both tubes, and I got the same issue with both of them, see that picture 



The bottom of the picture is 'stretched', and top is 'compressed' ! 

... which gives this with a game plugged 



Of course I've tried all the geometry/position/size potentiometers, and none can't remove me that strange problem.
As I said, I've tried that chassis on two different tubes, and got the exact result!

Here's a view of the chassis :





Any idea why this chassis has TWO rows for the tube deflection connection? I mean one row of 4 pins is enough? What is the purpose of have TWO of them?   



Of course I plugged the tube on both of them, and didn't noticed any difference...

Oh, and what is the purpose of this selector :



...it can be set on "W" (factory setting) or "N". What does this mean? I didn't try the "N" position.

Any idea about the whole problem? Could this be because this chassis is built as 20" and I'm using 19" tube? The production description is not totally clear :

Technical Features:
 
Power Input: 96-240VAC Free Voltage (Power Consumption <60W)
Input Signal: RGB Comp Synch GND (Colours Max 5V P-P) (Synch 2-4V Neg Edge)
Focus:  Electrostatic
Convergence: Self Convergence
Deflection Yoke Match: LH - 1.92mH  LV - 30mH  RH - 2.0 Ohm  RV 13.5 Ohm
H Synch: POLARITY 1Vp-p ~ 5Vp-p : FREQUENCY: 15.75 KHZ : PLUSE LENGTH: 3us ~ 7us
V Synch: FREQUENCY: 48HZ ~ 55HZ : PLUSE LENGTH: 190us ~ 500us
Tube size: 48cms/ 20"

I guess I should check the deflection yoke tube values. How to to that?

[Etienne MacGyver]

That would be my first guess also, an incompatible Yoke maybe..

Although the overall picture looks in good order..

Anyway,

RH - 2.0 Ohm  RV 13.5 Ohm

I think you need to measure the resistence of each coil.

i think they mean RH - Resistence Horizontal and RV - Resistence Vertical.

[lesoleil70]

5 yr old thread - love it!

What's that yellow stuff coming out of the base of the black capacitors?   That doesn't look very healthy from this seat, cheap leaky caps?

[level42]

That's glue to fix the caps mechanically.

I wouldn't be surprised if there would be a bad cap on that chassis.....do you have an ESR tester ?