Hantarex polo 28" sparking inside neck. Solved.
- Thread starter kissedin
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R177 was changed to R82 (0,7 W) during these tests. All resistors were changed to the list that mkl presented in this thread.
After trying the new values we changed back r170 to the original value (150 kohm) see what result that would bring.
Then the hot failed but that is probably because of that capacitor. Which I need to order.
New capacitor c172 and transistors arrived today. Also all resistors are still changed according to MKL's list.
First thing I noticed was that the sound when the tube is firing up was more gentle. Picture looked stable. The vertical is able to fill the screen. But not the horizontal. That is a problem.
(Note: I have not done the mod to use hr7191-fkyback instead of original eldor but as I understood that doesn't interfere with picture width).
I've only used the h-amp on the board at the back. Would it be wise or stupid to start tamper with the h-width coil?
First thing I noticed was that the sound when the tube is firing up was more gentle. Picture looked stable. The vertical is able to fill the screen. But not the horizontal. That is a problem.
(Note: I have not done the mod to use hr7191-fkyback instead of original eldor but as I understood that doesn't interfere with picture width).
I've only used the h-amp on the board at the back. Would it be wise or stupid to start tamper with the h-width coil?
The Panasonic tube you're using may be more akin to the Videocolor ECY family aka Medium Planar. Here are the schematics of this version:
https://postimg.cc/k6DJ85gN
The capacitance of C170 is higher, 820nF vs 330nF. If you have a 470nF cap rated 250V or 400V you could put it in parallel with the current one on the copper side.
Same for C175, 22nF vs 12nF.
It's the version with separate and non-adjustable bridge and EW coils (on the other version both are wound on the same bobbin with adjustable core):
https://postimg.cc/k6DJ85gN
The capacitance of C170 is higher, 820nF vs 330nF. If you have a 470nF cap rated 250V or 400V you could put it in parallel with the current one on the copper side.
Same for C175, 22nF vs 12nF.
It's the version with separate and non-adjustable bridge and EW coils (on the other version both are wound on the same bobbin with adjustable core):
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MKL: it seems that the link isn't working anymore.
I'll try and change the cap values at C170 and maybe C175 if c170 proves not to be enough. Capacitor at c175 is rated 630V so it may be harder to come by.
Again, thank you for your help. I wouldn't come this far without it.
I'll try and change the cap values at C170 and maybe C175 if c170 proves not to be enough. Capacitor at c175 is rated 630V so it may be harder to come by.
Again, thank you for your help. I wouldn't come this far without it.
Thank you again mr. MKL.
I recently got home from work and tried the H.freq. for some reason this got the picture wider. And now the whole screen is filled with a beautiful grey raster.
B+ is steady at 144.8 V and life isn't so bad after all. Since I have the whole screen filled I won't bother to change any caps.
But I do have a question regarding the HV-caps. For c172 I use this:
(I got this cap from a list here: https://forums.arcade-museum.com/threads/hantarex-polo-resistors.495735/
But it is a MKP capacitor and not a KP. KP for film/foil and MKP for metallized film. The schematics is quite clear on replacing these caps with exactly the same. But further reading suggests that the difference isn't that big anymore since MKP has developed
epci-academy.com
Since I don't fully understand (and I couldn't find any kp caps on mouser with the specified ratings) I wonder if anyone can explain what using a mkp cap instead of KP might result in.
Next step is to hook it up to time crisis 2 and see what happens. I'll keep this thread updated.
I recently got home from work and tried the H.freq. for some reason this got the picture wider. And now the whole screen is filled with a beautiful grey raster.
B+ is steady at 144.8 V and life isn't so bad after all. Since I have the whole screen filled I won't bother to change any caps.
But I do have a question regarding the HV-caps. For c172 I use this:
(I got this cap from a list here: https://forums.arcade-museum.com/threads/hantarex-polo-resistors.495735/
But it is a MKP capacitor and not a KP. KP for film/foil and MKP for metallized film. The schematics is quite clear on replacing these caps with exactly the same. But further reading suggests that the difference isn't that big anymore since MKP has developed
POLYPROPYLENE CAPACITORS PP / KP and MKP - EPCI Academy
Capacitors Basics & Technologies Open Course Film and Foil Organic Dielectric Capacitors POLYPROPYLENE CAPACITORS PP / KP and MKP C 2.4 POLYPROPYLENE (PP) / KP and MKP In the book we use the common European abbreviations KP for film/foil and MKP for metallized film. C 2.4.1 Introduction...
epci-academy.com
Since I don't fully understand (and I couldn't find any kp caps on mouser with the specified ratings) I wonder if anyone can explain what using a mkp cap instead of KP might result in.
Next step is to hook it up to time crisis 2 and see what happens. I'll keep this thread updated.
Changed c172, c174 and c175 (all possible culprits according to flow chart).
(Also ordered c170 but got 0.39uf (usa polo) instead of 0.33uf which is the correct for eu chassis. So decided to not change that one. Neither c183 (hesitated when it was of another type than original cap but this shouldn't be a problem according to schematics). Will change them both when I get the correct c170.
That was the boring stuff.
Hooked up the chassi to a neo-geo mvs. Got a decent picture. The first minutes the screen's brightness was shifting ocassionally. Like there was loose contact in the brightness pot, or worse - the G2 pot. But after say 20 minutes the brightness stabilized.
Some minor problems however.
The grid is leaning on the screens right side. A matter of some e-w/pin cushion adjustments? (How are one supposed to manuever those pots without getting killed? They are literally in the most dangerous place possible, behind a ground shield and the flyback.)
When displaying certain colors like white there is a pattern on the screen, almost like a fingerprint. (Dont mind the dark screen, photo was taken when the video shift from white to black since this phenomenon is most salient then). Any ideas?
(Also ordered c170 but got 0.39uf (usa polo) instead of 0.33uf which is the correct for eu chassis. So decided to not change that one. Neither c183 (hesitated when it was of another type than original cap but this shouldn't be a problem according to schematics). Will change them both when I get the correct c170.
That was the boring stuff.
Hooked up the chassi to a neo-geo mvs. Got a decent picture. The first minutes the screen's brightness was shifting ocassionally. Like there was loose contact in the brightness pot, or worse - the G2 pot. But after say 20 minutes the brightness stabilized.
Some minor problems however.
The grid is leaning on the screens right side. A matter of some e-w/pin cushion adjustments? (How are one supposed to manuever those pots without getting killed? They are literally in the most dangerous place possible, behind a ground shield and the flyback.)
When displaying certain colors like white there is a pattern on the screen, almost like a fingerprint. (Dont mind the dark screen, photo was taken when the video shift from white to black since this phenomenon is most salient then). Any ideas?
The first picture with the full grid looks pretty good to me. A touch of the pincushion pot should fix the right edge but it will have an effect on the left one too. The knob can be inserted in the pot from the copper side too if that makes it more comfortable to adjust.
The "fingerprint" artifact looks like a moire effect. Can you notice if it's related to the H freq adjustment?
Is the copper braid on the back of the CRT well connected to the neckboard?
The "fingerprint" artifact looks like a moire effect. Can you notice if it's related to the H freq adjustment?
Is the copper braid on the back of the CRT well connected to the neckboard?
I would like to say yes. I used the tubes original braid and crimped on a new female. I also reflowed the pin on the neckboard. I get 0 ohms when measuring metal frame to braid connector.
Regarding the moire effect. I adjusted h.freq until screen couldn't sync but saw no difference. For the record I'd like to add that the he camera amplifies this effect quite alot. In reality it isn't that bad.
Got rid of the moire effect...
Found the advice on Philips (!) homepage to adjust h.width. But that didn't do anything.
But when I adjust v.size the moire problem disappears. But then I don't fill the screen. Photo shows maximum vertical size before the moire-effect kicks in.
I tried to take a photo of the moire gone, but on camera everything looks the same.
Another odd behaviour is if I turn up v.size so it's overscanning. It is like the electron beam get stuck on lower part of screen and form a compressed pattern and a very bright horizontal line.
Would it be a good try to change back R177 and R170 to their orginal values? This since they are involved in the vertical amplication and yoke settings.
Feels like I'm almost there now.
Found the advice on Philips (!) homepage to adjust h.width. But that didn't do anything.
But when I adjust v.size the moire problem disappears. But then I don't fill the screen. Photo shows maximum vertical size before the moire-effect kicks in.
I tried to take a photo of the moire gone, but on camera everything looks the same.
Another odd behaviour is if I turn up v.size so it's overscanning. It is like the electron beam get stuck on lower part of screen and form a compressed pattern and a very bright horizontal line.
Would it be a good try to change back R177 and R170 to their orginal values? This since they are involved in the vertical amplication and yoke settings.
Feels like I'm almost there now.
Yes. But it didn't affect the moire effect. Only vertical size seem to do that. I can mask the problem by turning up contrast (but I prefer to keep contrast at minimum on hantarex polo in general since the picture tend to blur somewhat with it).
As I can remember there was no moire-effect with the original resistors. Maybe I'll try to swap r170 (now 120k) to a slightly higher value like 130 khoms.
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It's time to wrap this up.
All capacitors in the hv-circuit has now been changed to new ones. As well as the electrolytic ones. I've never seen a chassi this clean.
Screen to the left is the replacement tube. Don't mind the extreme moire-effect - it's just the camera playing tricks.
When connected to time crisis 2 the horizontal amplification is just enough to fill upp the screen. The moire-effect is still there if you look for it but otherwise not. In order to get the guns to register over the whole screen contrast had to be cranked up (this had to be done on both screens). This further hid the moire effect.
All in all I'm very happy with the result! Thank you ukvac and especially MKL and gunblade for all your help.
All capacitors in the hv-circuit has now been changed to new ones. As well as the electrolytic ones. I've never seen a chassi this clean.
Screen to the left is the replacement tube. Don't mind the extreme moire-effect - it's just the camera playing tricks.
When connected to time crisis 2 the horizontal amplification is just enough to fill upp the screen. The moire-effect is still there if you look for it but otherwise not. In order to get the guns to register over the whole screen contrast had to be cranked up (this had to be done on both screens). This further hid the moire effect.
All in all I'm very happy with the result! Thank you ukvac and especially MKL and gunblade for all your help.
A small update. After some time I decided to actually play a game (!) on my TC2 cabinet. A new problem immediately made its entrance: picture was very blury at first. It took around 20 mins until picture was good.
Googled and found that this may be a result of wrong heater voltage. The Hantarex use the flyback for heater voltage which means that the frequency is too high for my fluke 179 (maximum frequency for ac voltage = 1 kHz).
I connected my oscilloscope (via an iso trafo) to pins 9 and 10 on crt-socket. Heater voltage measured 5.5 VAC.
I changed resistor r35 to 1 ohm and got 6.05 VAC. Changed R35 to 0.82 ohm and got 6.33 VAC.
After this change it is a matter of seconds before picture is sharp when starting cold.
Googled and found that this may be a result of wrong heater voltage. The Hantarex use the flyback for heater voltage which means that the frequency is too high for my fluke 179 (maximum frequency for ac voltage = 1 kHz).
I connected my oscilloscope (via an iso trafo) to pins 9 and 10 on crt-socket. Heater voltage measured 5.5 VAC.
I changed resistor r35 to 1 ohm and got 6.05 VAC. Changed R35 to 0.82 ohm and got 6.33 VAC.
After this change it is a matter of seconds before picture is sharp when starting cold.
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