OT: Panaplex/power issues



#5

I have several calculators, Canon, Victor, Monroe that have Panaplex (or Panaplex type) displays. I noticed after sitting for weeks and power them on, it takes 30-180 seconds before the display lights up. If turned on multiple times a day they light up immediately. If turned on once a day they will light up in 1-10 seconds.

Is this a "common" phenomenon of old Panaplex/type displays? i.e. related to the display driver circuitry or is this type of behavior indicative of the main unit power supply?

The units are Canon F-11, Victor 1800-1721, Monroe 1920.
Other desktops, of the same age, with LEDs and don't experience the problem.

thanks


#6

Yes, this is common. I have many calculators with Panaplex or similar displays including the Victor and Monroe that you mentioned and this is their normal behavior. Some of the Sanyo ICC series machines, the ICC-811 comes to mind, can take up to 30 seconds to warm up.

I believe the issue is that the high-voltage inverter needed to run the display takes a while to both start oscillating and to "form" the high-voltage storage capacitor. Replacing that cap with a new, low-leakage one will lessen the latter problem.


#7

Doh, you beat me by a minute :)

#8

Since these require high voltage, I assume a faulty (dried up) capacitor within the HV circuit. Replacing all capacitors close to the coil (might look like a square block) should help. Howevery sometimes (rather often than rarely) an encapsulated assembly has been used, I don't think those could be repaired.


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