Tek 222/224 Battery Replacement - Project Update

Jeff Davis

Hi all,

I'm happy to announce that the Tek 222/224 Battery Replacement project is complete. I'm in the process of testing and shipping the first 25 orders from deposits received from folks here on TekScopes; after that, I've got another 14 boards available before I would have to go back and get some more built.

For those of you unfamiliar with the project, the Tektronix 222 and variants such as the 224 were sold originally with a sealed lead-acid (SLA) battery. Replacements for these SLA batteries stopped being manufactured a long time ago and, due to the form factor of the original battery, there are very few available SLA batteries that can be made to fit in the scope.

This kit allows the use of up to three readily available 18650 rechargeable lithium batteries to replace the now unavailable SLA battery. No modifications to the scope are required other than removal of the original SLA battery. Charging and protection circuitry is provided, allowing the use of unprotected 18650 cells. The kit consists of one assembled and tested battery charger circuit board, one 3D printed case, and some miscellaneous parts such as light pipes to bring the LED indicators to the front of the case and a jumper cable to attach to the scope’s battery connector. The kit does not include rechargeable 18650 lithium batteries (required for operation).

Here's a link to the order page: https://www.n0dy.com/product/tekcharger/.

For those of you interested in the history of the project, I maintained a status page with updates on progress at https://www.n0dy.com/2020/03/29/tek-222-224-charger-order-status/,

Some technical details from the original circuit designer can be found at http://kitsune-denshi.net/projects:tek222bat.

Best regards,
Jeff / N0DY

From: Jeff Davis
Sent: Thursday, March 26, 2020 10:02 AM
To: TekScopes <TekScopes@groups.io>
Subject: Tek 222/224 Battery Replacement

Hi all,

One of my customers approached me a few weeks ago about a project to replace the sealed lead acid battery (now unobtainium) in Tek 222/224 scopes with lithium ion cells that presumably will continue to be available for the foreseeable future. He pointed me to a really well done project with a public domain license. There's a YouTube video on it - https://youtu.be/LJ2VS3aohV0.

After a couple of weeks of capturing schematics, sourcing parts, etc. I'm about ready to hit Send on an order for the PCBs. Before I do that, however, I wanted to check with the community to see if there's sufficient interest to order more than the minimum quantity of boards.

How about it, Tek 222/224 collectors? Any interest in a battery pack replacement based on the design in the YouTube video above?

Jeff / N0DY

Join TekScopes@groups.io to automatically receive all group messages.