VOGONS


First post, by Imperious

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I purchased this Cypress scaler from a UK based Auction house Ebay site for roughly $70 Australian delivered, which is a good price for one of these.
Unfortunately it's dead as a Dodo apart from the fact that the power Led lights up.
I got about $60 of the $70 refunded, I think You don't get the Auction house fee refunded. That sucks a bit but they don't want it returned so I'm
going to see if I can fix it.
I purchased this model as I know it's compatible with 720x400 Dos resolution, based on a Youtube clip out there.
The reason the LED lights up is it's directly connected to the DC jack.
After some poking around with the multimeter I found that after the switch IC the 5v rail is 19.3 ohms to ground. From there the
rail goes off to 2 3.3v regulators as well as a 2.5v regulator. There is a 1.8v regulator but that is fed from the output of the 3.3v regulators.
The regulators outputs are all ok and none have any low resistances to ground. The 19.3 ohms is also across any capacitors on the 5v rail.
I initially started removing a capacitor as well as the DC jack to get at the 8 pin switch ic (Fet) which I thought might be the culprit. As it turned out
the Fet does not have any pins to ground so that cannot be the problem. I next removed three of the regulators but the 19.3 ohm is still there.
Eventually I found that there is a diode on the underside that measures 19.3 ohms and after removing it the low resistance to ground is gone.
Tomorrow I'll stop into Jaycar and pick up a new DC jack, and if lucky I might be able to find a 6.8v zener and capacitor at work. Ill update this once I
have got the parts and fitted them as well as put the 3 regulators back.

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Atari 2600, TI994a, Vic20, c64, ZX Spectrum 128, Amstrad CPC464, Atari 65XE, Commodore Plus/4, Amiga 500
PC's from XT 8088, 486, Pentium MMX, K6, Athlon, P3, P4, 775, to current Ryzen 2600.

Reply 1 of 7, by Imperious

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Just a quick update of no success yet. I have put the regulators back on, replaced the capacitor and zener diode but I have 1v output from the Fet in the
power stage. It's possible the Fet is stuffed, will replace that next and see what happens.

Atari 2600, TI994a, Vic20, c64, ZX Spectrum 128, Amstrad CPC464, Atari 65XE, Commodore Plus/4, Amiga 500
PC's from XT 8088, 486, Pentium MMX, K6, Athlon, P3, P4, 775, to current Ryzen 2600.

Reply 2 of 7, by Rawit

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Do you have any idea which exact model this is? I have a Cypress scaler but it's not so good. Scaling quality is bad, black levels are incorrect and everything is stretched to 1920 pixels. Also, Hz in == Hz out with mine, so if you output 70 Hz and tend to use this on a LCD which is limited to 60 Hz input you will get an "out of range" or the likes of.

My build: Speedsys

Reply 3 of 7, by Imperious

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It's a Cypress CP-293. I have attached the pdf. Looks like it supports output of multiple resolutions.
My monitor is an LG 144hz 32iinch, so Vertical Frequency will not be an issue.
it doesn't specifically state that it supports 720x400 but I found a Youtube clip that shows this working.

If it doesn't work good enough (that's if I can fix it of course), I'll just get an OSSC.

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Atari 2600, TI994a, Vic20, c64, ZX Spectrum 128, Amstrad CPC464, Atari 65XE, Commodore Plus/4, Amiga 500
PC's from XT 8088, 486, Pentium MMX, K6, Athlon, P3, P4, 775, to current Ryzen 2600.

Reply 4 of 7, by Rawit

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That unit seems to have a lot in common with the Gefen VGA to HDMI scaler, the manual seems to indicate the same. If it's the same, quality should be really good. Try pressing the + and - buttons to reset the device. When not connected to power for a long time it sometimes outputs a signal that my display won't accept.

My build: Speedsys

Reply 5 of 7, by MAZter

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looks like Atlona AT-HD500 scaler clone (perfect device).

try to connect it to different monitor,

when I set a certain non-standard resolution, the monitor works with it, but the HDMI video capture device refuses to see the image

Last edited by Stiletto on 2020-03-02, 06:44. Edited 1 time in total.

Doom is what you want (c) MAZter

Reply 6 of 7, by SirNickity

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Imperious wrote:

The regulators outputs are all ok and none have any low resistances to ground. The 19.3 ohms is also across any capacitors on the 5v rail.

That being the case, the most likely culprit is that the main IC is shot. Not a lot you can do about that. There is also what looks like a ROM chip in that square socket, so it could be that... but you would probably spend more on an EEPROM burner, and possibly a replacement chip, than you would've spent on the converter at full price. That's assuming you can get a good copy of the ROM image.

I don't mean to be negative, but these sorts of devices are basically an I/O and power harness for the black box that is the main IC. If the harness isn't totally kaput, there isn't much left. IMO, you're tossing time and money into a pit replacing passives and hoping for signs of life. (Which is fine -- I've done it too, when the potential reward is worth it -- just don't spend more than you're willing to lose trying to resuscitate it.)

BTW, the OSSC cannot do framerate conversion either, it's just a line multiplier. So your display will have to support 70Hz either way. Personally, I haven't had much of a problem with format compatibility, although I'm using PC monitors and a single LG TV that seems to be fairly accommodating.

Reply 7 of 7, by Imperious

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Thanks for the replies. I'm trying to fix this just to see how far I can get. So far I have identified what I thought to be an eeprom is in fact a Winbond/Nuvoton 78e365 Microcontroller.
I ended up removing the Fet then jumpering the 5v Across to the output. I spent ages figuring out where traces go which helped me identify certain parts of the circuit.
To cut a long and possibly boring story short the 22.1184mhz crystal on the Microcontroller does not work at all. I didn't realise at the time that my multimeter only reads frequency
up to 19.99mhz so after realising that I thought that the crystal was likely ok. All other crystals on the board are oscillating ok. I borrowed a 60mhz capable oscilloscope/meter from work
and proved the crystal is dead. I fitted a 16mhz one in there and that works ok but of course that's not the frequency it's supposed to be working at. I did manage to get some life from the
micro and could measure some activity on the address pins but no other life signs.
So at this point I have ordered some 22.1184mhz crystals from RS Components, so by the end of this week will know whether it works or not.

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Atari 2600, TI994a, Vic20, c64, ZX Spectrum 128, Amstrad CPC464, Atari 65XE, Commodore Plus/4, Amiga 500
PC's from XT 8088, 486, Pentium MMX, K6, Athlon, P3, P4, 775, to current Ryzen 2600.