26 August 2012

Scope Sunday 36

I recently came to the unbelievable, shocking realization that I haven't bought any additional scopes since I helped clean out that barn last December.  I felt that it was necessary to rectify the situation... However, despite attending the monthly MIT Swapfests this summer, several Electronic Flea Markets in California, and even the Hamvention in Dayton back in May, I haven't found anything worth dragging home.  (I've bought several plug-ins (stories for another time), but no new scopes or mainframes.)

Luckily, my friend Will reminded me that this was Boxboro weekend, so I drove up to Boxborough, Mass. Saturday morning, and looked around.  There was a dirty 564B for $200 (which is at least 10dB too high, $20 would be about right), a 7834 for $100, and several 7603s around the flea market, but the things that caught my eye were two 422 scopes (at two different sellers).

The 422 is a 15-MHz portable scope that had an optional battery pack.  The one on the left (serial number around 33,000) has the AC/DC power supply and the battery pack, but it doesn't power up.  The one on the right (SN around 12,000) works, but it has one bad channel, a broken handle, and no battery (it's AC only).  I'm hoping that they both can be fixed, but I should be able to get at least one of them working easily.

They aren't great scopes, but they remind me of a missed opportunity...  Several years ago on eBay, there was an auction for a whole pallet of broken 422 scopes.  If I recall correctly, there were 30 or 40 of them.  I thought seriously about buying them all and using them as the basis for great class project: student teams would study, troubleshoot, and fix the broken scopes.  The more scopes you fixed, the higher your grade!

I really should have done that.


Unknown said...

a class project of fixing oscilloscopes?!?!?!?!? can you move to California and start teaching at Sacramento State? I would take every class you offered. We only have 3 analog EEE professors as it is!

Ulf K said...

I have a 422 in my museum. The battery module is loaded with NiCAD cells.

At least in Sweden, it is not possible to buy them anymore.

From what I think, it should be possible to remove the battery package and mechanically reconfigure the 422 to be an AC-only, but I am not to sure about it.

joe charge said...

I think you mean 20dB for $200/$20.

Doctor Analog said...

@joe Money is power, therefore $200/$20 = 10dB.

@Ulf It's still possible to get NiCads in the US, or I could try replacing them with NiMH. I'd really like to get the battery pack working again... A battery-powered scope is a cool thing (especially of this vintage).

Martin said...

hello Jim,

422 is a fine scope, I have 3 of them (all from heerenveen). There is 2 versions: the older use 3 nuvis, the newer FET.

greetings from germany