I have two 7904 frames and two 7904a frames looking for new homes located in Kalamazoo, MI. One of the 7904a has no trace, the others worked when last used. Appropriate time bases and vertical modules

Tektronix tended to have a square pad on circuit boards on the positive side for the capacitors... also square pad on banded end of diodes... Jim n8qoh

I've used an HP 3478A on low ohms setting looking for the best short across the tantalum capacitors, followed by clipping one leadand applying power (the second shorted tantalum then lost the magic sm

The Radio Shack desoldering iron was very functional with a bit of modification. I used a doorbell transformer, full wave bridge, windshield washer pump, Gerber baby food jar with two brass inserts in

I have a Uni-T UT81B that I bought to troubleshoot some Tek 2247 power supplies. Works ok, build quality is a bit rough inside. I use a Rigol MSO1104Z for a bench scope, I don't hate, or like it any m

Where is the board located? This one has a 9 pin ?serial and a parallel port? on the back. The video board has the dreaded custom chip failure, so it can be parted out. Jim N8QOH Sent from Yahoo Mail

At 10 I was making things like electric motors out of nails, wire supports, electrical tape and brass strips. Probably inspired by the Boy Electrician or some other book. Took apart TV's, built a lot

The Uni-T UT81C at 8 Mhz is a good compromise. Its a meter, frequency counter, single channel scope. $154 from eBay.It comes with the BNC adapter, you need to buy a separate 1x/10x scope probe for $10

A friend brought over two broken 2246's for me to repair. Unit 1. Channel 1 & 2 both displayed the calibration square wave signal as a flat line with spikes up and down for the transitions. Visualinsp

I can give you a hint based on repairing one with a horizontal amplifier issue in the last year. Look for a shorted tantalum capacitor and a burned out current limiting resistor.If it is the same fail

It has been five years since I had to change the last one, and it was a 2753P which is sort of a 494AP? in a rack mount case. It is an actual light bulb, I think I got 5 in the envelope when I ordered

I would second the suggestion that a grain-of-wheat bulb has failed. I have replaced them before on two units. Jim Cottonn8qoh To: TekScopes@... Sent: Wednesday, October 26, 2016 9:55 AM S

Build a noise source (SRD or zener) and amplify it, then use peak hold. Otherwise buy a cheap Chinese DDS board with a sweep function and display and use peak hold. Or build a tracking generator... ht

There is a lot less information available about them than the 49x series,which they share a lot of parts with. Dave at Artek Media can tell you if the service information is available. Jim To: TekScop

Another consideration is you want shottky diodes on each string that you tie in parallel to the power point tracker in case a string is shadowed. Generally in front of each PPT there are a number of s

To: TekScopes@... Sent: Tuesday, March 1, 2016 3:02 PM Subject: Re: [TekScopes] TM 505 vs TM515 Jim You might want to check that out again ....according to the manuals I have.,the TM503 do

I prefer the TM503. No fan.Less depth, more working space.Stack two, then you have two high power slots. Jim Cottonn8qoh To: TekScopes@... Sent: Tuesday, March 1, 2016 12:55 PM Subject: [T

You have a lot of reading to do. High vacuum, high voltage, x-rays, a neutron source. You need to join and read the fusor forum, the yahoo gamma spectroscopy and Geiger counter groups. You may find yo

When I was in high school I used the cheap radio shack desoldering tool and removed the bulb. Some tubing along with a gerber baby jar with two brass inserts soldered in the top for an accumulator wit

Motorola Exorsizer (sp?) I have one in the basement with manuals and floppies, condition unknown. Many different boards. Not economical to ship I suspect. Who knows how the media is holding up. Kalama