Thu Aug 29 2019

Leica CM1900. Solenoids not getting power

Hi, working on the CM1900. Driving me crazy. First problem: bad CFM. Replaced it. Second problem: bad starting circuit on one compressor. Replaced that. Third problem: bad compressor. Replaced that. Now the problem Im having is that the neither of the 3 solenoids are opening up. No voltage going to them in normal operation but do get voltage during test mode. Got a solid 24 VDC input to the circuit board. No voltage at the output. Please help! Thank you so much!!

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Sat Aug 31 2019Reply from Paul_8779
avatar placemark

I'm trying to remember (3) solenoids.  Right now I can only think of the main chamber defrost solenoid which is powered only during defrost.  Which other 2 are you referring to?  

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Mon Sep 02 2019Reply from Winter S
avatar placemark

Hi Navy Guy,

Yep this sectioning machine looks like the board has some broken components. In fact the point that you had to replace so many parts initially is probably because the board is overloaded.

I've seen these multiple type problems on boards that had machines plugged in during a power surge at the hospital. Usually a lightning strike. 

Hospitals tend to be taller buildings in the surrounding areas.


If there are 24Volts inbound and 0 Volts outbound, the board is the problem. BUT, there still is hope. Have a look at some options (below).

There are other things to consider to get this sectioner to keep on ticking.

1. Contact a repairman that specializes in medical equipment. This includes the local computer repair shop. You see,...these boards are just computer boards. And sometimes with a good repair guy that works on boards...they can simply replace the components on the board that are blew out. He will know by looking at the caps and transisters under a microscope lamp. If they are bulging then he can replace them by soldering new ones on. yep

2. try to fix it yourself, by buying the parts and fixing the machine.

3. buy a used cryo sectioner - This option is sort of new in the world of medical equipment. It was only 5-6 years ago when this became a serious option. The equipment can usually be purchased from one of the many used medical equipment suppliers online. However, there are only a few places to put the sale into an auction format to pick up some really good deals. One is Mazree at

4. the last option is to buy new through the normal supplier. This is last because it is the most expensive. But doable, depending upon your hospital purchasing budget.

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Tue Sep 03 2019Reply from navyguy
avatar placemark

Hi Winter S,

Thanks for the great input.

The seized compressor and worn out condenser fan motor were isolated parts that went bad and doutbful there is any connection to an overloaded power output board. Yes, I would agree that power going into the power and zero power leaving the board is a good indication of a bad board but Im trying to be really careful before condeming the board. This could be a "sucker bait" situation. Ive fallen for it several times before. What throws me is that in test mode, each solenoid is getting power which tells me that the board is able to power the solenoids. Just not doing it in normal operation mode.

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