Electronics > Repair
Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
TERRA Operative:
Take a look at pages 8, 11 and 30 of the datasheet coromonadalix posted, it might help get you started.
KungFuJosh:
I did, but...
--- Quote from: KungFuJosh on August 28, 2024, 11:42:32 pm ---Even still, it might be above my paygrade. 😉
--- End quote ---
Looking at those charts doesn't tell me any specific details about what component/value I would need to change to reduce the minor ghosting present. 🤷
coromonadalix:
some notes on p15 p16
3. V0, V12, V43, V5 pin
4. VLCD = VDD - VEE, V0 = VDD = 5V, V5= VEE = -23 V
V12 = VDD-2/n(VLCD), V43 = VEE+2/n(VLCD), n = 17 (1/256 duty, 1/17 bias)
5. V0 = VDD, V12 = 1.71V(VDD = 5V) or -0.06V (VDD = 3V),
V43 = -19.71 V(VDD = 5V) or -19.94V (VDD = 3V), V5 = VEE = -23V, no-load condition (1/256 duty, 1/17 bias)
i never saw an lcd with the same ic's for column and row, for sure the voltage thing is something ..... scratching my head
and the missing 8 pins soic, some of them or one of them would-could be a negative supply generator (i think) not installed
maybe theses calculation may help to fine tune the resistors ? and the lm324 could act as buffer(s) something since it's a quad op amp
KungFuJosh:
U8 is "negative pressure" according to the seller, and it's currently installed. The seller told me to try it again. It didn't affect the ghosting, but maybe made the flicker worse. That is to say, the flicker wasn't noticeable with my other values, but now there's a hint of it with U8 installed.
ETA: I reduced R4 to 3.9k and the flicker is gone with U8 installed.
coromonadalix:
maybe in all of this it's a matter of getting the multiples voltages and get the right duty cycles ... you have to check your older lcd to see at what it was, and fit the new as such
could be some timing issues at some point for the ghosting when it happens
the Hioki must use strict settings, and most of the glcd 320x240 could be out of it, there is so many on the market, so many ic's etc ...
to fit with the motherboard SED1335F driver, it work at 1/2-duty to 1/256-duty LCD drive
maybe at some point, you may have to live with it like this ???
your original Powertip can be found (post #14), but some say compatible on ebay, but over 75$ is a huge rip off
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