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Pat,

The trace location is under the graticule intensity knob on the left. Likely the contacts are dirty. C1194 and/or C1181 is the one you are talking about with the corroded lead. The first one I put in a film type. The output decoupling, I used a 56mfd 100V Nichicon UHE type since I had these in stock. C937 could be bad giving you the higher ripple than you want on the negative supply for the crt. If you replace it, use a high temperature, low ESR type that is 35V, e.g. Nichicon ULD or UHE type. The capacitance is not critical so if you put in a larger value, it is fine. Do not lower the capacitance. A 47mfd to replace a 50mfd is close enough, not something like 33mfd or less. You could increase the value of C966 to lower the ripple.

The slow warming could be the 8393 Nuvistors are weak, if yours is old enough to use them.

Mark

Where is the trace finder typically located on a 453? Anywhere, centered who knows?

Dug out the 453 last week and started looking into maybe or hopefully getting it going again. It looks like the X axis is out of whack as I can see the CRT glow as I move the vertical position move up and down and all those years of owning it I have never used the Trace Finder function. The Trace Finder in Auto Trigger shows a tiny trace a little over 1/2 of a division and 2 divisions left of center with the Horizontal Position knob centered. Checked the voltages and all looked in order however I can’t see any ripple but loads of noise in the order of 40 volts on the HV(-1950) and 20mv on the +75 volt supply and 15 to 20mv on the + and -12 volt supplies. Those were taken with the digital oscilloscope but did use the Fluke to confirm the voltages. That’s about as far as I have gotten so far aside from poking around for several hours looking for something loose. I do have a leaky small cap on the power supply board as there is corrosion on the lead of it in the +75volt side(10uf or less). That was the only thing that looked out of place as I was quite impressed with how nice it looks inside. Only problem I had in the past was the fan bearings as one of them was making a lot of noise and had to replace them back in the late 80’s.

I replaced my old 453 several years ago as I was loosing the trace on the 453. It started slowly as it took longer and longer to warm up but in the meantime I had been researching budget digitals and purchased one. Went to do some audio work about a year after purchase of the digital and it totally stunk for doing audio work. Got out the 453 and it took forever to get the old 453 going but did get the job done and chased down the problems for the stage lighting while I had it working. I found a nice Japanese 40Mhz scope at a hamfest for $20 and been using it for audio work and does a fine job. I purchased the 453 in 1980 after I graduated High school and has been like a family member.

I am new to the group and have been enjoying the research as I recently acquired a 7854.

Take care
Pat

Interleaved, at least what I can answer

On 4/23/2022 7:50 PM, jimbert4 via groups.io wrote:

1) The procedure calls for a Time-Mark Generator. Is this really just a pulse generator? What is the pulse width?

Tektronix time mark generators can put out narrow spikes with a sharp leading edge (so you can tell where it is).? They generally have intervals from 1 ns down, although the 1,2 and 5 ns pulses are more sinewaves than not.

2) Is the Time-Mark a positive pulse, i.e. it does not go below gnd in its low state?

Wouldn't matter if it did, all you're looking at is the interval between leading edges.

3) What should the amplitude of the Time-Mark be set to?

Enough to give you a good presentation.? The idea is time and risetime, not amplitude so much.

4) The procedure says to adjust the deltaREF control to intensify the 2nd (for example) time marker and adjust the delta control to intensify the 10th time marker. Okay, I understand that. Then it says to superimpose the delayed B Sweep time markers within 0.2 division. Not sure about this. I see the 2 magnified (B?) sweeps, so am I supposed to adjust them to align the edges on top of each other? Is that like a fine control on adjusting the times? Does it matter which delta control(s) I use to make this fine adjustment?

This has been covered in similar questions, you might try 2465 calibration.? Since I don't have one, I've not studied the procedure.

5) The final Time-Mark setting is for 20ns (50MHz). My waveform generator only goes to 30MHz. Could I use a 40ns (25MHz) square wave and count edges instead of time marks?

I suspect so, but it needs to be 50% symmetric as a good guess.

Harvey

1) The procedure calls for a Time-Mark Generator. Is this really just a pulse generator? What is the pulse width?

2) Is the Time-Mark a positive pulse, i.e. it does not go below gnd in its low state?

3) What should the amplitude of the Time-Mark be set to?

4) The procedure says to adjust the deltaREF control to intensify the 2nd (for example) time marker and adjust the delta control to intensify the 10th time marker. Okay, I understand that. Then it says to superimpose the delayed B Sweep time markers within 0.2 division. Not sure about this. I see the 2 magnified (B?) sweeps, so am I supposed to adjust them to align the edges on top of each other? Is that like a fine control on adjusting the times? Does it matter which delta control(s) I use to make this fine adjustment?

5) The final Time-Mark setting is for 20ns (50MHz). My waveform generator only goes to 30MHz. Could I use a 40ns (25MHz) square wave and count edges instead of time marks?

Looks like Ken uploaded it to TekScopes;

/g/TekScopes/files/P6021%20Amplifier.pdf

George

He confirmed red glyptal.



David J. Brown

vintageTEK President

Yes, there is information on the web that covers it. I haven't done the modification. I just purchased my 2465BDM in 2016 for $100.00 +$53 shipping off of epay.

I replaced the Back-up Battery, fixed a couple of problems it had, rebuilt the Power Supply (replaced the Aluminum Electrolytics and the X & Y EMI Conducted Emission Suppression Capacitors, a couple of power Resistors too), replaced other Capacitors that needed replacing.

I sent it off to Alex Schonfeld for Calibration. He was also able to add the Video Option Board and Counter Timer Option Board. So, it is fully loaded, now. Been running great for many years.

Ross

On Sat, Apr 23, 2022 at 07:32 AM, Albert Otten wrote:

067-0652-00 Peak to Peak Detector

Jeff, note it's 067-0625-00. Albert

And THAT is exactly how I lucked into this item: the part number was mistyped by the seller and that probably hid it from any other prospective buyers.

— Jeff Dutky

I uploaded a Electronic Design idea from a few decades ago for a simple amplifier for the P6021. I haven't built it so I can't attest to it.

Ken

067-0652-00 Peak to Peak Detector

Jeff, note it's 067-0625-00. Albert

Jared,

Yes, it had occurred to me that adding a couple hundred mV to the battery voltage would require changes to the surrounding resistors to get back to a target voltage that correctly offsets the Vf of the rectifier diodes. I had not done the calculation, however, to know what the new resistor values should be.

Interestingly there is a later version of this same fixture that replaces the mercury cells with alkaline manganese oxide batteries (probably because the mercury cells were no longer available). I was going to consult the service manual for that later fixture to get an idea of what they did to account for the higher voltage of the alkaline cells.

I see that I can buy manganese oxide cells from Murata and they look like similar form factor to the cells I see in my unit, only thinner. I’m thinking about how to make a parallel multi-cell pack that will fit in the current space.

The mercury cells seem to be less prone to leakage than some modern alkaline cells. I’m also interested in what I can do to prevent leakage from the replacement cells inside the enclosure.

— Jeff Dutky

If you swap to Alkaline cells, swap R10 and R11 to 200K resistors to bring the adjustment of the trimpots back into a useable range due to the higher cell voltage over the original ones.

Also, to those who emailed me, I'll reply this weekend, the last few weeks have been insane at work etc...

I lucked into a 067-0652-00 Peak to Peak Detector on eBay for much less than the going rate. When it arrived I immediately opened it up and checked the batteries. They read only about 1.25 V, while the service manual indicates that they are supposed to be 1.35 V mercury cells. I expect that the drop in voltage indicates that the batteries are spent.

It looks like silver-oxide batteries are close in voltage, as are a couple of extant lithium chemistries (e.g. Li-CuO, Li-CuS, and Li-FeS), but it's not clear I can get them in a button cell size that will match the existing mercury cells.

What is the suggested replacement for these batteries?

-- Jeff Dutky

This is what I got for these scopes:

4X EEMB ER17335 Nonrechargeable 3.6V Lithium Battery with Tabs Li-SOCL? 2/3A Size 2100mAh High Capacity UL Certified Single-Use 3.6V Lithium Thionyl Chloride

Free shipping from Amazon when ordered with a bunch of other items.


- Bert

Yep, I'm sure those "customer is also supplier" kinds of situations happen a lot.

I read about a company making pulse generators. They used IIRC Motorola transistors in the pulsers, which Moto in turn used to test their transistors. Supply chains got stressed at one point, and Moto received a new pulser, but it didn't work at all. No output, so they opened it up. Inside was a board with no transistors and a note saying something like "We shipped. You SOBs didn't!"

And I'd heard of a similar situation at Orthodyne Electronics where I worked for a couple of years back in the early 2000s. They made wirebonders that used Apex power op amps (to drive the ultrasonic transducers to cause the wire and substrate pads to cold fuse) which were chip-and-wire hybrids. But Apex used the Orthodyne bonders to produce the op amp hybrids! They got into a chicken-and-egg situation, but instead of writing nasty notes, VPs from both companies got together and worked something out.

Come to think of it, my first job out of college in the late 1980's and early 1990's also had that kind of situation. I worked for Lockheed at the Skunk Works on the U2 project. Lockheed had E-Systems (ironically now part of Raytheon Technologies where I currently work) building some systems that went into the wing pods of the U2. But E-Systems had subcontracted the Lockheed lab where I worked to build fiber optic links to connect their systems in the two pods. So E-Systems was both vendor and customer.

Jim Ford

That’s hilarious, Bob. Thanks for that part of the story. I hadn’t heard before about returning the gifts!

Cheers
Tom

Sent from my iThing; please forgive the typos and brevity

Roman,

I’m seeing somewhat less compared to what you see on the 200 mV DC range. And it varies between plug-ins with one being ~6 mV highest and the lowest being ~2 mV. Of course shorting the input zeros out the reading.

What is interesting is that when placing the EXT/INT switch on INT the offset minimizes. A quick look at the schematic shows several functions being switched in different parts of the circuit aside from merely transferring from the front panel jack to the rear card edge connector finger. I don’t have time right now to investigate why.

I also have a couple of DM502As and threw them in a TM frame. They read 0.1 and 0.2 mV with the input open (not shorted). Pushing the EXT/INT switch didn’t change the reading either nor did shorting the input. So I suspect that they need to go through the zero calibration process spelled out in the manual.

The manual provides some helpful block diagrams showing switching and signal routing that may assist you with your investigation. And one other thought - have you checked for any ripple in the DC supply lines from the TM frame power supply just to make sure that it isn’t helping this issue? And how clean are the card edge finger contacts? A slightly elevated ground condition through dirty fingers can cause many strange artifacts as well.

Greg

That's too expensive for me.? It's nothing more than the ring and BNC from a standard tektronix probe with the ID pin shorted to ground.? I need to get around to making one.

Harvey

If you are going to use the P6021 with a 7A14 the part number of the adapter is 131-0750-00. There is a guy peddling the adapter in new condition on ePay.

The 7A14 can also use the P6019, P6020 and P6022 current probes. But use with the P6019 and P6020 probes results in reduced performance.

Greg

Steve,

You are correct. While working in Denver television at the ripe old age of 18 I worked with RCA TR-3, TR-4 and TR-70 machines and all had built-in video monitors and scopes. The scopes were specifically designed for video monitoring using pushbuttons to select what you wanted to view.

Not to date myself but I also worked on two RCA TRT-1’s (RCA's first video tape machine product) which had (4) 7-foot racks of fire-breathing vacuum tubes. After getting the TRs we then donated the TRTs to Denver Fire Department who had just set up a microwave video training system to their fire stations and was in need of VTRs. I ended up training the fire guys on maintenance and such but they quickly realized that these monsters were going to be a big liability both time and cost-wise.

Greg