Wallace and Tiernan Series 1500 pressure gauge

[NC-Cals]

I have a Wallace & Tiernan Series 65-120 pneumatic calibrator with a Wiki Series 1500 pressure gauge (-3.6 to 30.6 psi) analog pressure gauge. The first rotation of the gauge to 14 psi is right on, but it drops off as you approach 30.6 psi. It's only allowed ±0.02 psi (0.066% FS). I have contacted Wiki services and they don't have adjustment specifics and are not taking new work due to lack of parts and backlog. Does anyone have any information on how to adjust these? I'm a K3/4 guy, but I know enough that if you trial and error the adjustment you'll just frustrate yourself and probably make thing a lot worse.

[USMCPMEL]

Put up a picture. It has been a while but I have adjusted them in the past. Are you sure on that tolerance?? That seems awful tight.

[USMCPMEL]

I looked up the paperwork on the last one I did. The tolerance listed is +/-.03 not sure if that helps you any?

[NC-Cals]

I contacted Wika to see if they could calibrate it but they said they aren't taking any new work. They have a 6-month turnaround time minimum. Longer if it needs parts due to availability. They also wouldn't give(sell) me the adjustment procedure. The accuracy is ±0.066% FS and the gauge range is -3.6 to 30.6 psig. Here is the gauge. https://www.bucksales.com/wika/precision-gauges/images/1500-gage.jpg
Luckily my client accepted a limited calibration.

[USMCPMEL]

Is your dog a golden??

I tyhink in the past the ones I used to work on I would ever so slightly ofset it at zero.I do not think I have seen one of those in a few years though.
How far out was it?

[NC-Cals]

Kiko was a labradoodle...he died a couple years ago.
The gauge was allowed ±0.02 and it was low by 0.05 psig

[USMCPMEL]

Sorry for your loss, We have a golden retriever great dog.