EBME Forums Forums Maintenance Technical Assistance Ultrasound Machine Problem - help please

Hello, back again to find help in thie great forum

I have an ultrasound machine, chinese one called Emperor, it is a new device, and works very well, but suddenly, the sector where the image should be, became white !!
All the display and other things are ok, but no picture, just white picture, with both probles, vaginal and convix.
I can hear the whine from the probe, but no picture, only white picture.
What could be the problem?? or where should i work first??
I can take a photo for any part and post here if needed.

Please help..

Greetings
Ahmed

Hello again Ahmed. How are you doing out there?

It could be anything, Mate. What steps have you taken so far?

PS: a new unit? No service manual, then?

Fast reply as usual Geoff, thanks a lot dear.

Untill now, i have checked power circuits and they are ok, and the transmit/recieve circuit look ok, but, the op-amp of the recieve circuit are getting very hot, they are six ICs AD8332, they get really hot even without a probe connected.
I have removed three of them and nothing happened.
Could they broken all together?? the six in one shoot !!
No service manual anywhere, i have searched here and there but nothing.
The problem started oneday about five monthes ago, sometimes they get that white picture, and sometimes works fine, untill it decided not to go back ever
I can hear the relays ticking normally when the device boots, and it senses the probes normally, i mean when you remove the probe, you get "no probe" message, in both inlets.

BTW, this is the device

I don't know where to start !


Greetings
Ahmed

I would suspect something to do with the display itself ... but I'm just guessing.

Unless (if you're lucky) it's something daft like a faulty brightness control, or some such thing!

Are there any video outputs (connectors) available? If so, what do you get on those?

Otherwise ... maybe it's time to consider purchasing another cheap Chinese unit!

Thanks, thw whole screen is ok, the whole system is ok, only the examined picture is white all the time, birghtness and contrast affecting the whole screen, and they work fine.
Also i have tried exterlan monitor and a video printer, all the same, good screen elements with a white sector !!

Looking for another device to change PCB's, and determine where is the problem.

I will post any results here upon progres.


Thanks a million man, the world is beautiful with people like you.


Greetings

Thank you for your kind words there, Ahmed.

Actually I had better confess that I should have absorbed your original post a little better ... but never mind.

OK, it sounds like some board swapping could be the way forward. From what you have said, I guess that you've already had the unit open and had a good poke around for loose connections and such?

Yes i have, even net level to IC's lose pins and shorted transistors and resistor measuring.
Even next level to remove the op-amp IC's (6) to see what could happen.

Nothing happens at all !!

I feel like it will end up delivering the unit to the agent technical section but it will cost a lot, so i am doing my best solving the problem myself.

Greetings and thanks a lot



Ahmed

Hi ahonda55,

did you check the HV voltage supply to Transmitte-receive board? It's about 80VDC to 120VDC depend on the kinds of unit. If yes, you go on to find out DSC board (DIgital scan converter )Its position is near of T-R board and check all voltage supply at the connector and test points of board,you touch on the ICs's back if some chips are too hot abnormal you can be sure this board has problem.
DSC digitalized the analog signal from T-R board and process to make the echo video signal in the convex area. In the case the convex area is full blank (like milk ) , I think the problem is DSC board

Thanks hung, the unit have only four boards, transmitter-reciever board, socket and relays board, CPU board, powersupply board, and also the screen have it's own board.

On the T-R board i can find 50 volts and 60 volts on some small transistors, i think this is what you mean.
The T-R board have 6 op-amp's, each chip is a dual op-amp, so there are actually 12, and some components and 6 A/D converters.
Also on the T-R board there is a microprocessor, so i think the T-R board works also as a DSC boards.

The op-amp's gets very hot even with no probe connected !!

I will take some photos to share here.

Greetings and thanks a lot.

Ahmed

But can the op-amp chips get broken all in the same time?? and i have removed them and nothing happened, the same white image.