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Be careful with that! Danger, 640 Ohms!

I do not know if it applies to this type of scope. However, I have had knobs appear to be seized when in truth the knob has slid down the shaft and is binding on the back of the knob to the chassis.

4 NiCd = 5 volts. No, this is just a outside fast signal source to test the triggering ability. I test the TDs in a curve tracer ( carefully !!! ). Then follow up using a tunnel dipper. Tunnel diodes

I have been using my 454A for 40 years and never had any problems. I love it! They are one of the most reliable scopes Tek has built. Nick

That is a good question. The similar 100 MHz 2247A specifications divide the total bandwidth into two frequency ranges at 25 MHz and say that peak voltage measurements above 25 MHz follow the trigger

<john@...> wrote: So far the best oil I have found for small fan bushings and bearings is heavy gear oil like you would use in a transmission or differential. I poured some into a needle

So posting is all correct except for a calling it a current probe. Thank you for the leg work. I should likely have noticed the part number with less than 'normal' digits.. and guessed it a prior

Looking for confirmation of my understanding of the Tek specs for automatic voltage measurement in the 2400 series scopes. Am I right in understanding that automatic voltage measurement is spec'ed to

It's not too hard. Just a disassemble, clean and grease if not gone too far.

So, is the 4 AAA == 6 Volts and the divide by ten == .6 Volts a level that tests the TDs well? It's just below a normal .7V diode drop, so it tests their "tunneling" ability?

Another point - download both service manuals and take a look at what's involved in fixing each of them. The 46x series tends to develop bad filter caps and rectifiers. It is possible to replace them

While the comments are valid for 454, the 454A (as listed in the subject) does have a larger screen and FET input circuitry.? So, if Frank truly has a 454A available its more of a level playing field

Update: I soldered an IC socket in U174 thinking that I would connect leads to it externally to diagnose the Ch1 issue and now the trace has completely disappeared! The beam finder works, but when I

640 ohms ought to be enough for anyone.

I recently obtained a batch of old and diverse probes. Many are junk but a few are rather interesting. Out of a number of old 1x Tek probes I should be able to put together 2 nice ones (as soon as a

My manual, for SN B250000 and up, does in fact say "check the collector of Q984", so you're right. Raymond

Hi, In an original paper high S/N 475 manual (B250000 and up) it only says Q984 on page 4-16 in step 2. There is no mention of a Q3984. tom jobe...

Stand the scope on it's rear and dribble small amounts of De-Oxit down the shaft. Let it sit for an hour, then try turning the pots. 73, Dick, W1KSZ

Neither of my 475 manuals have a page 4-16. I did not find the section of the manual you are referring to. <javier.alberola.perales@...> wrote:

Hi, I'm trying to repair a 475 following the procedure in the manual. In the page 4-16, paragraph "sweep and logic", step 2, the manual says to "check the collector of (3984". Is this an errata, and