Hantarex MTC 9000 Hissing... Flyback?

[DaveJ-UK]

My MTC 9000 is hissing loudly when it's powered on. After 20 minutes or so when it's warmed up a bit, it gets quieter and quieter until you can barely hear it. It also sometimes pops a few times and the screen flickers when it's just powered on, but this only happens in the first couple of minutes if it happens at all.

I've only just replaced all the caps. It had a couple of other issues before I replaced the caps (red colour seemed to come and go) and adjusting controls wouldn't get rid of jail bars. These problems are no longer present, but the hissing remains.

I'm not really sure where the hissing is coming from because it's all in such a tight space, but I reckon it might be coming from the flyback. Am I right to suspect the flyback? I know they're not that expensive, but it's still $25 + shipping to the UK from Zanen.

[MonitorGuru]

You may have broken the core free in the flyback. Stick a toothpick between the core and the edge of the flyback and see if that helps. 

First check if THATS where the sound is actually cominig from though----with the monitor on, take a long cardboard tube, like from a paper towel roll and point it at various parts of the monitor and listen to diagnose exactly where the sound is coming from first.

The other possibilities are:
- That you didn't reattach the anode cap fully, or only got one of the two terminals on the anode wire "stuck" under the glass under the anode cap.  If it's this, DISCHARGE, remove, respread the tabs and correctly reattach the anode.

- Didn't correctly reattach the ground wire around the tube and its no longer touching a good portion of aquadag (the black stuff on the outside of the tube)

Check these 3 things, using the cardboard tube to diagnose where the noise is coming from and report back.

[DaveJ-UK]

Thanks for the quick reply.

The hissing was there before I replaced the caps.

I've just double checked everything apart from the anode cap, although I did triple check this originally as I wanted to make sure I did it properly before I turned on! I remember tugging on it lightly without squeezing the pins and it seemed to be well attached.

I never messed with the ground wire around the tube, it just unplugged from the chasis. In fact, I didn't mess with the tube or other wiring at all, I just unplugged everything from the chasis, did the work and plugged it all back in.

The monitor has been on for an hour or so now and it's not making the hissing noise any more.

[MonitorGuru]

If it's not the flyback buzzing, then you probably have cold solder joints (solder that has broken free from the trace).. This could explain the popping/jumping...possibly.  Let it cool, turn it back on, then listen through the tube to pinpoint where it is at. Will help in locating it.

[DaveJ-UK]

OK I've found the source of the hissing, assuming of course that there is only one source.

It's caused by arcing (spelling?) from the anode cap wire (thick red one) where it comes out of the top of the flyback, to part of the chasis metal.

Please advise. Thanks.

UPDATE: I've managed to eliminate the arcing by putting a thin bit of plastic (from a butter tub lid) in between the place on the flyback where it's coming from the and the chasis where it's jumping to. Interestingly, at first it still made the hissing noise. Then I put another bit of blastic in other side of the flyback, which eliminated the hiss and tiny visible blue sparks completely.

[Ken Layton]

Flyback is bad. You could clean that area where it arcs off neatly and dob on a glob of common silicone glue to insulate it. Generally though when a flyback starts to arc like that it means it's going to crap out soon so the best bet is to replace it. Flybacks are a very common failure on Hantarex monitors. You could buy a replacement from the UK office of Happ Controls.

Happ Controls Europe, Ltd.
Unit 7, Hornet Close
Pyson Industrial Estate
Broadstairs, Kent CT10 2Yd
Phone: 44-1843-871-100

[DaveJ-UK]

Thanks Ken.

I gave Happ Controls a ring on 01843 871100 today and they told me that they were closing (!?) and all sales were now being dealt with by another company who's name escapes me, and to give them a ring on 0208 3361300.

I called them and they asked me what model flyback I wanted. Being at work and not knowing I would need this info, I could only tell them the make/model of the monitor.

I'm just at home now and I'm looking at the flyback, but it has rather a lot of markings. On the front (between the screen and focus controls) is written "MHF 023-21", then a logo consisting of "CM" below, followed by "5503". There's also a "1" in the top left (still looking at the front), followed by "2" in the top right, then 3, and finally 4 in the bottom left. "HR" is also written on the top.

On the left side is written;

DIEMEN 95-43

HR 1APC 7025-00

4120

--

I have absolutely no idea what any of that means! From that lot, can any of you guys tell me what model it is, as I won't have it in front of me when I'm at work?

[Ken Layton]

The original Hantarex part number is 28021200 which is also the same as HR Diemen part number HR7025. Hope that helps.

By the way, I didn't know Happ Controls was closing the UK office. Who is taking it over?

[DaveJ-UK]

Phoned them back this afternoon and they want

[ebo0763]

Anyone knows what flyback HR 1APC 7107-00 is? I found an NOS but no clue what it's for.

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[grantspain]

Anyone knows what flyback HR 1APC 7107-00 is? I found an NOS but no clue what it's for.

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mtc9110 and some U.S version mtc9000

[ebo0763]

Thank you!

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