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Main => Monitor/Video Forum => Topic started by: simondwilliams on August 30, 2021, 11:08:19 am

Title: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: simondwilliams on August 30, 2021, 11:08:19 am

Hello,

I have a KORTEK KTN20 CRT Chassis I see AC input is 120 could you confirm if I need a isolation  transformer ? Or could I connect directly AC 110 V on the two 120V leads ?

I blew the R601 5W 0.47ohm ceramic resistance on it and wondering if it because I plug the ac inputs the wrong way or because isolation transformer not present.

https://archive.org/details/korteksejooktn20colorrasterdisplaymonitorinstructionmanual (https://archive.org/details/korteksejooktn20colorrasterdisplaymonitorinstructionmanual)

If isolation transformer is needed would you provide a good place and sku for one please ?

Thank you

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: grantspain on August 30, 2021, 06:30:06 pm

120-128vac iso on these chassis
the other two wire that have been cut are 240vac for the degauss although if in the usa you can cross them them to the 120v pins

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: simondwilliams on August 31, 2021, 10:59:03 am

Ok I understand that I do need a Isolation transformer

For the degauss from what I understand it will not work is not crossed to the 120v leads ?


Thank you very much for your reply :)

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: grantspain on August 31, 2021, 03:14:41 pm

yes the degauss will not function unless you link over the 120ac - so pin 1 to pin 3 and pin 2 to pin 4

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: grantspain on August 31, 2021, 04:04:53 pm

and obviously replace the missing fuse

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: simondwilliams on September 02, 2021, 09:40:17 am

Good will do, good notice on the fuse :) Thanks

Ordered the parts, will keep you posted !

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: simondwilliams on September 14, 2021, 03:14:14 pm

Ok tried to replace fuse and the ceramic that blew up but nothing to do the fuses stills blows. I messed it up without the isolation transformer...

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: grantspain on September 14, 2021, 03:38:33 pm

the big ceramic resistor mounted on the frame looks damaged
i suspect the bridge rectifier at d601 is also bad
lots to go wrong in the power supply section of these

where is that burnt out terminal block with the blue wire going?

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: simondwilliams on September 14, 2021, 03:58:32 pm

It was to that Big ceramic R601

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: grantspain on September 14, 2021, 04:13:30 pm

i think the schems are not correct, my chassis has a 12 ohm 30 watt resistor
when you removed the old resistor the value should be printed on one side

do you have a str ic at ic601 or a transistor at q601- there are two very similar models and this helps id it

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: simondwilliams on September 15, 2021, 08:22:44 am

I removed the broken ceramic it is a 30W 12 ohm YUMI ceramic written on it :) It was connected to R601...

I cannot find ic601 but see a transistor at q601. Photos attached

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: grantspain on September 15, 2021, 08:47:16 am

next steps are to replace the resistor with correct value, check the bridge rectifier with a multimeter for any shorts and do the same with q601

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: simondwilliams on September 15, 2021, 10:42:46 am

Thanks for your help :)

ok order de ceramic from amazon... Now for the transitor check I google and found a video will get back to you as for the bridge rectifior where is it ?

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: grantspain on September 15, 2021, 11:23:04 am

D601 top right corner, almost as common as flyback failing these chassis

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: grantspain on September 16, 2021, 05:06:37 am

are you in the uk as that chassis would be rare in the usa imo

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: simondwilliams on September 16, 2021, 06:58:22 am

I am from Canada in the quebec province

Title: Re: Kortek 19 inch CRT Chassis for arcade AC INPUT on KTN20
Post by: grantspain on September 16, 2021, 07:43:04 am

ok no problem, if you were uk based the degauss would have wired direct to 240vac but i imagine you are same as usa on 120vac so the link wires will be correct for you on the ac input connector