El cheapo analyzer build.

[MaxE]

I am trying to build an EL cheapo clone analyzer. I have purchased the “Home Builders Bible for Analyzers” from OxyCheq but sourced the parts individually. So the plans are for a PM128-A digital panel meter but they are no longer available. The new models seems to be the PM128-E. Anyone who has built one recently recall what was sent with your kit? And or does anyone still have the plans and mind sharing? Again I have purchased the book from OxyCheq but it was written in 2001 and there seem to be some changes in 20 years, I’m not trying to get something for free just updated info.
Thanks.

 

[BRT]

I am trying to build an EL cheapo clone analyzer. I have purchased the “Home Builders Bible for Analyzers” from OxyCheq but sourced the parts individually. So the plans are for a PM128-A digital panel meter but they are no longer available. The new models seems to be the PM128-E. Anyone who has built one recently recall what was sent with your kit? And or does anyone still have the plans and mind sharing? Again I have purchased the book from OxyCheq but it was written in 2001 and there seem to be some changes in 20 years, I’m not trying to get something for free just updated info.
Thanks.

New 3-1/2 Digit LCD Panel Meter PM128A - Digital Panel Meters | Circuit Specialists

www.circuitspecialists.com

 

[MaxE]

New 3-1/2 Digit LCD Panel Meter PM128A - Digital Panel Meters | Circuit Specialists

www.circuitspecialists.com

Totally missed it. Thanks.

 

[BRT]

Totally missed it. Thanks.

I may have led you astray. The second Google search result is almost half the price.

PM-128A | LCD 3.5 Digit (13mm), 9VDC Independent

 

[BRT]

$10.95 on Amazon

 

[MaxE]

I think I can make this PM 128-E work if I can figure out where the R3 resistor on the 128-A is on the E….
I can get it to power on with a 9v battery and moved the decimal on the display.

Found it. Seems like it’s an almost identical board layout a little different and can do 9v or 5v. I’ll have to build it all the way out and get the sensor to confirm

Update: The wonderful folks at Oxychq confirmed so should be rolling soon. I’ll post photos when I get it done if it works.

 

[MaxE]

I may have led you astray. The second Google search result is almost half the price.

PM-128A | LCD 3.5 Digit (13mm), 9VDC Independent

Shipping and handling is amazing and typically the equalizer…

 

[MaxE]

So I have the analyzer together but I can’t get it to calibrate correctly. The range is like 21%-25.5%. I used a 100 ohm 10 turn potentiometer and a 360 ohm resistor. I’m guessing I need a resistor with a larger value but electrical engineering is not my area of expertise so not sure if some inverse thing is happening and really I need a smaller one? Another strange thing that may be related is that the potentiometer seems backwards, to reduce the percent the knob turns up…. So more playing is needed to to get it right.

 

[tursiops]

So I have the analyzer together but I can’t get it to calibrate correctly. The range is like 21%-25.5%. I used a 100 ohm 10 turn potentiometer and a 360 ohm resistor. I’m guessing I need a resistor with a larger value but electrical engineering is not my area of expertise so not sure if some inverse thing is happening and really I need a smaller one? Another strange thing that may be related is that the potentiometer seems backwards, to reduce the percent the knob turns up…. So more playing is needed to to get it right.

The pot probably has three leads, right? And you are using the middle lead and one of the outside leads, right? Move the outside lead to the OTHER outside lead.
Is the resistor in series with the pot, or in parallel?

 

[MaxE]

The is in series with the middle lead (in line) I had movies the outer lead wire and it was no better. I’ll play with it more when I have some resistors to play with and see what works. I need to get some tiny alligator clips