Hi Folks,
I picked up a 4½ digit 20V meter some time ago, I have altered the resistors for a 200mV reading and will need to move the decimal point one place to the right. Bridging the D3 holes, on the PCB, with a piece of wire I expected to see two decimal points, but the original had extinguished and only the new point showing. Does this mean that the solder bridge on connections D2 will not have to be removed? There are six connection points: D1 to D4 and F and H; what are the F and H for?
Many thanks, Blackbull

 

Have you got a number for the display/meter?

 

No, Beenthere, there is nothing printed on the front or on the IC, just the printing on the PCB for resistors required for 200V, 20V, 2V and 0.2V and decimal point connections.
Thanks for reply, Blackbull

 

Hello,

Can you post a close-up photo of the meter?
Both front and back will be handy.

Bertus

 

Hi Bertus,

Silly me when I removed the protective film from the front of the meter there is a number HB8145A and it is also on the PCB!!! I have Googled this number but my Chinese is a bit rusty! The datasheet does show only one bridge for each setting but does not show FH. As you may be able to see with a temporary bridge the decimal point has disappeared from the second place.

Thanks for you interest.

Blackbull

 

Hello,

I think the D1-D4 are for the decimal points.
The F could be for Fast and H could be for Hold.

Bertus

 

Bertus you are probably right about FH I will do some experiments; and also remove the bridge from D2, although de-soldering is not something I like to do.
Blackbull