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Main => Monitor/Video Forum => Topic started by: action76 on March 07, 2018, 02:52:01 pm

Title: U5000 Help! One with vertical collapse and one clicking.
Post by: action76 on March 07, 2018, 02:52:01 pm
I recently picked up three U5000 chassis in hope of getting at least one hopefully two going for a pair of Cruis'n USA cabs. One supposedly working, one unknown and the last looked to be a non working parts donor.
Chassis 1: It was set to CGA mode so I moved the middle connector to the 25kHz plug and removed the vertical sweep update kit connector from TP205. It fired up and was working however the picture was washed out. The contrast on the remote board was turned all the way down and the blacks still were too bright. If I turned the remote contrast pot up just a tiny bit everything start getting overblown and bleeding. Turning the brightness down helped the black level but made everything else too dark. I tried another remote board and I tried adjusting screen on the flyback and several other combinations and could not get it to look right. In the middle of my adjusting the monitor started to get wavy sometimes depending on what I was changing and then it shut off completely and now just does the click click click when turned on. I assume it is a power supply section issue but I am unsure what to look at first. Also, if I do get it going again, is something causing the washed out problem or am I just not adjusting it correctly?

Chassis 2: Hooked it up and it has vertical collapse. R303 is bad, D302 is bad, and the vertical IC (TDA1771) has a visible burnt spot on it, so I assume it is bad also. If I replace all these components, will that do the trick? What else should I check so I don't smoke those parts again because of another bad part? Also, the other board and the parts board has a jumper with a resistor on the bottom side from one of the pins of the Vertical IC. This board does not have that. Is that necessary? Could that be part of the problem that caused the collapse to begin with?

Thanks for any help you monitor gurus can give me.

Stephen
Title: Re: U5000 Help! One with vertical collapse and one clicking.
Post by: action76 on March 08, 2018, 09:45:16 am
Quick update on  Chassis 1: I found the HOT to be blown so that is the reason for the clicking.  I am going to replace it, but is there something I should look at beforehand that might have caused it to blow so I won't ruin another one when I replace it?
Title: Re: U5000 Help! One with vertical collapse and one clicking.
Post by: action76 on March 09, 2018, 09:47:20 am
Chassis 1 update: I replaced the HOT and swapped the flyback from the parts board I had.  I'm not sure the flyback was bad but someone mentioned that it was a good idea to change it because that could be the cause of the HOT blowing.  It fired up and I got raster on the tube.  I then hooked the cruis'n board up and it came up but it was out of sync.  I did not leave it on long and try to adjust it because the blacks still look to bright or gray.  I am going to do a full cap kit on it next just to be sure before I tinker with it too much and see how it looks then. 

Chassis 2: I am going to change the R303, D302 and the Vertical IC.  I would still like to know any suggestions of other things to check before I fire it up and blow them all again.
Title: Re: U5000 Help! One with vertical collapse and one clicking.
Post by: lilshawn on March 09, 2018, 12:02:59 pm
Chassis 1: flyback "screen" control needs to be turned down until the black is black.

Chassis 2: these chips overheat, especially if there is no heatsink paste, it's old and dried out... or it's poorly screwed down. common failure is dead short and burnout. the resistors that feed power into the chip get thrown out of spec too... replace them as well.

you are on the good track.