Wittig Oszifox Penscope, Radio Shack Probe Scope - Page 1
Forum section: electronics / general

author: Lightages
author_rank: Unknown
timestamp: June 08, 2012, 03:34:05 am
content: I have a RadioShack Probescope that I purchased in the mid 90s for $30, actually I purchased two for that price. This thread is a result of trying to not hijack another thread.The Probescope was one of the first real attempts I had seen at making something useful in a logic probe style case, especially at 20Mhz bandwidth! They did not sell well as far as I know and they went on clearance at Radio Shack. For the time they were actually quite cutting edge. I have used mine for many little field checks and at this they excel. They are good enough ti see if something is actually doing anything and if within the correct magnitude of operation. (http://www.eevblog.com/2012/06/04/eevblog-286-orders-of-magnitude/)These things were actually designed and made by a German company, Wittig. They called the thing an Oszifox Penscope. There are apparently at least two versions of the design, one with the Wittig name on the circuit board and one with the RadioShack name.Mine:One owned by A Hellene:The whole front end looks different and the small IC between the push buttons had the version sticker on it.I have yet to see anything to beat these pen scopes even today. The most recent attempt as reviewed here:https://www.eevblog.com/forum/product-reviews-photos-and-discussion/rps2050-pen-style-sope-review-teardown/appears to be a total failure.There is some documentation left on the web for the main chip in the scope, but some that I was able to find in the late 90s and 00s have disappeared.http://www.htmldatasheet.com/zmd/zm407.htmI have the full chip documentation that I printed out years ago and will scan and provide for those interested.

author: free_electron
author_rank: Super Contributor
timestamp: June 08, 2012, 06:22:12 am
content: a real east-german chip.. ZMD ( Zentrum Microelectronic Dresden .. )... They became part of AMI (Audtria Microsysteme , not to be confused with the other AMI : American Microsystems )and a COP processor from national !I have a waaay fancier thing laying around.. i'll post some teardown pictures of it if i find a minute. An Agilent LogicDart !

author: A Hellene
author_rank: Frequent Contributor
timestamp: June 08, 2012, 06:35:25 pm
content: Thank you for the Oszifox PenScope picture and information, Les!It seems to be the same design to theRadioShack ProbeScopeI purchased in the late nineties, which was based on theZM407 scope ICand the National SemiconductorCOP880 microcontroller.For our readers information, I purchased mine in the 1997 and paid a premium (USD ~80) for the RadioShack branding,as I wrote at the original thread. The extra components that can be seen at the top left of my PCB are a switchable 9.0 Mohm (= 4.7M + 4.3M) input resistor and a couple of capacitors that form a 10:1 AC compensated resistor divider with the 1.0 Mohm device input, in order for me to expand the 100Vpp max. input range and use the ProbeScope to reverse engineer and troubleshoot the CDI/TCI motorcycle ignition controllers I used to repair, upgrade and reprogram by that time. As expected, of course, I managed to kill the device by accidentally touching a ~300VDC output line of a CDI DC/DC converter while I was probing the low voltage section of the PCB, with the 9.0 Mohm front-end bypassed...Though the ProbeScope was not an accurate device, it was great to give you a quick view of the waveform the probed lines had. Then, you could use the DMM or the scope for more details.-George

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 08, 2012, 09:03:24 pm
content: ALthough the newer OLED units are pretty rubbish I think they still beat the OSZIFOX & similar if for no other reason that they have internal battery. More so once you add a proper on/off switch and remove the beeper

author: Lightages
author_rank: Unknown
timestamp: June 08, 2012, 10:08:25 pm
content: Quote from: mikeselectricstuff on June 08, 2012, 09:03:24 pmHmmmm... but are they $200 better when paid $30 for mine?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 08, 2012, 11:22:16 pm
content: Quote from: Lightages on June 08, 2012, 10:08:25 pmThe cheapest OLED one, with similar bandwidth is $105 - if you actually _NEED_ a tool like this, that's not a big deal. Cost is more of a consideration whan it's just a fun toy..