Hoshizaki control board no lights

[Tropicalice]

The test ststem does noting…

Is the 16 volts dc not too high? Should it not be 12v ?

The board has date also.

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[fixbear]

Yea, that’s a obsolete board. And the machine was built in July 2001.

[fixbear]

When you rectify AC power to DC, you are actually reading the peak. It will always be higher than the input AC. Even with the diode voltage drop. I wiould think the DC should be about 14V. But in your case, I suspect that the board power control circuit is bad. The HT1 area of the board. The probable cause can be a cap, resistor, or power transistor. U6 transistor, C12, 13, 14. L! and L2 resistors. They have a clamping power supply to protect the board. You friend that looked at the board might have a variable ac power supply. If so before condemning the board, power it with 11V and slowly bring it to 12.3 that you read on the machine. If the power light lights during this test you know the transformer is off.

Buy the way, Measure your input power voltage to the machine. It has a working range of 104V to 127V. Hopefully you have a true RMS meter. You may have harmonics in the building.

[Tropicalice]

Do you know the number that is written on the

power transistor ? I cant read off the number anymore as it faded away.

Or is there a schematic where i can read of the values and numbers of caps and transistor of that particular board?

[fixbear]

Unfortunately , no. If the number is gone, it’s from heat. A sure sign of probable failure. And being there are so many SMT components, They are hard to find values on. Plus, you have to have a SMT station to do any board work. Mine was $700 years ago. I don’t know the circumstances of this machine, but you will probably be farther ahead just ordering the board. The replacement will be a Alpine board. So make sure to read the service manual (not just browse) to understand the dip switch settings and what you machine has for a configuration.