Test and Measurement Forum

I have ac measurement only on channel b but not a dc is good on both. what can be done? have down loaded latest software, no change.

Hi rich,

This seems to be a hardware problem. If you wish to return the unit for repairs then you can email us at support@picotech.com with your contact details and return address along with a brief description of the problem we can generate a returns number and instructions on what you need to do to return the unit.

Kind regards.

This is down to the two input relays on each channel that switch between the AC & DC function. These relays are readily available from Farnell and easy to replace. They are of a reed type and simply get 'sticky'.

My 'scope is doing to same.

No ability to select AC coupling on channel A but channel B is working in both AC and DC coupled modes.

I initially thought it was some sort of software bug but hopefully reading this post has sent me in the correct direction.

I've popped the lid on the scope and can see two Hamlin relays.

One is part code HE3621A0510 (Farnell 9561927, £4.00) this is a SPST-NO relay, perhaps it has stuck closed, leaving the AC coupling capacitor permanently shorted out?

There is another relay HE721C0510 (Farnell 9561765, £3.83) this is a SPDT-CO relay.

Can anyone enlighten me as to which relay does what?

Perhaps I should replace both, unless anyone can advise otherwise?

Hi we do not provide any repair information.

You would have to return the unit to us for repairs. Please email us at support@picotech.com if you wish to do so.

Kind regards

Just to let people know that replacing both the relays did indeed fix the 'scope.