Hanterex chassis to tv tube

[Retroman839]

Yeah, unfrotunately that's a horizontal pot, you need a vertical pot for the neckboard. Unless you solder a jumper wire onto the single leg to the neckboard

Sorry that has lost
Me



So no good To swap with that top one ?
For the green drive ?..

I thought 470 ohms and I’m good .. it has same foot print size ?

 

[Retroman839]

Had a little de soldering practice .


Flyback maches hr diemen 7118.

polo 25/28 ?

 

[tb2000]

Wow how did you push the centre rof the pot out? A assume the bits on the back of the pot holding it together must've become weak. Yeah the 470ohm side of things is correct, but it's orientation isn't. You need a vertical pot - if you lay the neckboard flat, the pot stands vertically off of the board. The 470ohm pot you have sits horizontally or flat to the board - for example the same way the big B+ pot sits in the psu section of the chassis. So with the board flat, instead of adjusting it from the side for example, you'd be adjusting it from the top. As I say, you can make it work though by soldering in the two legs that are side by side into the corresponding holes left behind by the vertical pot, but you'd need to extend the single leg on the other side of the pot to reach into the single hole in the neckboard left by the single leg of the vertical pot. It appears that you have some vertical pots in that pic of stuff you've desoldered. I assume it came from the chassis of the Fidelity TV you got the crt from? To be honest, i'd get a proper Piher (or similar) pot from Mouser or eBay or something, make sure you get the 10mm version and not the 15mm version. I might have a spare if you can't get one. The HR7188 lopt you've got won't work in a 25"/28" Polo as the pinout is quite different to an HR7191. That said, it isn't impossible, the lopt would need strapping up to something near to the lopt solder point holes in the chassis and the legs would need adapting with wires to direct them into the correct holes. With the HV it gives out though, it'd probably be more suited to a 20" chassis like a MTC9000 perhaps, I think it's missing an output for the 200v line to work properly on a Polo. Best person to ask about something like that is member M K L.

 

[Retroman839]

Wow how did you push the centre rof the pot out? A assume the bits on the back of the pot holding it together must've become weak. Yeah the 470ohm side of things is correct, but it's orientation isn't. You need a vertical pot - if you lay the neckboard flat, the pot stands vertically off of the board. The 470ohm pot you have sits horizontally or flat to the board - for example the same way the big B+ pot sits in the psu section of the chassis. So with the board flat, instead of adjusting it from the side for example, you'd be adjusting it from the top. As I say, you can make it work though by soldering in the two legs that are side by side into the corresponding holes left behind by the vertical pot, but you'd need to extend the single leg on the other side of the pot to reach into the single hole in the neckboard left by the single leg of the vertical pot. It appears that you have some vertical pots in that pic of stuff you've desoldered. I assume it came from the chassis of the Fidelity TV you got the crt from? To be honest, i'd get a proper Piher (or similar) pot from Mouser or eBay or something, make sure you get the 10mm version and not the 15mm version. I might have a spare if you can't get one. The HR7188 lopt you've got won't work in a 25"/28" Polo as the pinout is quite different to an HR7191. That said, it isn't impossible, the lopt would need strapping up to something near to the lopt solder point holes in the chassis and the legs would need adapting with wires to direct them into the correct holes. With the HV it gives out though, it'd probably be more suited to a 20" chassis like a MTC9000 perhaps, I think it's missing an output for the 200v line to work properly on a Polo. Best person to ask about something like that is member M K L.

Yeh from the fidelity ..
I just removed to practice
Desoldering..
I will check my other junkers chassis pots also ..
I don’t mind a jumper wire on the pot .. if it solves the problem . I have actually solved it kinda anyway now,
needed turning down !
And it’s now down on both green pots and looks fine ..
issue of if flicking still happening but almost non visible. 👍

I will look see what other pots I have tomorrow

 

[M K L]

The HR7188 lopt you've got won't work in a 25"/28" Polo as the pinout is quite different to an HR7191. That said, it isn't impossible, the lopt would need strapping up to something near to the lopt solder point holes in the chassis and the legs would need adapting with wires to direct them into the correct holes. With the HV it gives out though, it'd probably be more suited to a 20" chassis like a MTC9000 perhaps, I think it's missing an output for the 200v line to work properly on a Polo. Best person to ask about something like that is member M K L.

Thanks for the heads up! I've checked the HR7188 and the Fidelity ZX3000 schematics and this is yet another flyback that could be adapted for most Hantarex 20" chassis (MTC900E through to Polo/3). It has everything that's needed (video B+ is on pin 7 btw).

 

[Retroman839]

Thanks for the heads up! I've checked the HR7188 and the Fidelity ZX3000 schematics and this is yet another flyback that could be adapted for most Hantarex 20" chassis (MTC900E through to Polo/3). It has everything that's needed (video B+ is on pin 7 btw).

When you say adapted ..
Do you mean
Jumper wires for pins that are not in correct position for a chassis. As mentioned above ?
Thnx 👍

Sounds good as I have 2 hantarex 20” that last time I tested ( only plugged in )
We’re both non working
Só this maybe gives me a possible ave to go down.

 

[M K L]

It's a project I'm going to do/show in the future. Ignore it for the time being (but keep that TV flyback).

 

[Retroman839]

It's a project I'm going to do/show in the future. Ignore it for the time being (but keep that TV flyback).

argh ok .. cool ..
This will be good ..
I could look at my chassis same time perhaps 😉

 

[PfefferT]

Wow how did you push the centre rof the pot out? A assume the bits on the back of the pot holding it together must've become weak. Yeah the 470ohm side of things is correct, but it's orientation isn't. You need a vertical pot - if you lay the neckboard flat, the pot stands vertically off of the board. The 470ohm pot you have sits horizontally or flat to the board - for example the same way the big B+ pot sits in the psu section of the chassis. So with the board flat, instead of adjusting it from the side for example, you'd be adjusting it from the top. As I say, you can make it work though by soldering in the two legs that are side by side into the corresponding holes left behind by the vertical pot, but you'd need to extend the single leg on the other side of the pot to reach into the single hole in the neckboard left by the single leg of the vertical pot. It appears that you have some vertical pots in that pic of stuff you've desoldered. I assume it came from the chassis of the Fidelity TV you got the crt from? To be honest, i'd get a proper Piher (or similar) pot from Mouser or eBay or something, make sure you get the 10mm version and not the 15mm version. I might have a spare if you can't get one. The HR7188 lopt you've got won't work in a 25"/28" Polo as the pinout is quite different to an HR7191. That said, it isn't impossible, the lopt would need strapping up to something near to the lopt solder point holes in the chassis and the legs would need adapting with wires to direct them into the correct holes. With the HV it gives out though, it'd probably be more suited to a 20" chassis like a MTC9000 perhaps, I think it's missing an output for the 200v line to work properly on a Polo. Best person to ask about something like that is member M K L. Change your WordPress theme the right way — keep your content intact

That’s actually a really clever workaround for the pot orientation issue. Not ideal, but definitely one of those “make it work with what you have” arcade repair moments.

 

[Retroman839]

Used a cap leg

 

[Retroman839]

I did a little vídeo to show the green issue a bit better ..

Today it causes the heater bars to come up and they were all green.
15 May 2026

 

[gunblade]

that mtc900e for you, i would replace both bf871, both pots and check all diodes on the green circuit and then expect the other colours to fail soon
and use new parts not reclaim

 

[Retroman839]

Thanks grant ..
I will get them parts orderd up
Will change all them bf871

 

[gunblade]

don't forget the diodes, they are glass type and corrode - they tend to fall apart, 1N4148

 

[Retroman839]

don't forget the diodes, they are glass type and corrode - they tend to fall apart, 1N4148

I about to ask about these
Are they on kneck card as well . Same circuit

 

[gunblade]

yes look at the schem

 

[Retroman839]

yes look at the schem

All parts on way 👍
Will get em in, and update .
Thanks ..

 

[tb2000]

I see you've bought the relevant parts now to renew the BF871's etc! Was going to say, it's up to you, but if you want me to sort this out by all means send it back.

 

[Retroman839]

All parts on way 👍
Will get em in

I see you've bought the relevant parts now to renew the BF871's etc! Was going to say, it's up to you, but if you want me to sort this out by all means send it back.

yes please I would like to take you up on that offer 👍

All picture now gone.

Some magic smoke
From I think this little resister down by the flyback



I will dm you mate