High voltage probe and oscilloscope

i use my HV probe to discharge the anode all the time. is this good or bad use of the HV
probe? so far its been doing me good for the last 20+ years with no issues. zero.

It's the perfect/safe use for the HV probe, the CRT and yourself.
It measures and it discharges (in a controlled manner); 2-in-1 function. LOL :)
 
Planning on buying the following items:


B&K PRECISION HV 44A high voltage probe for setting the voltage in my tempest hv cage wg6100.

Also thinking of buying the Hantek DSO5202P oscilloscope for general testing of pcbs.

Any input as to if these items are acceptable would be appreciated

Thanks

Per the other (correct) comments, I have this exact HV probe. It's great for discharging tubes but the analog gauge is so small that it's nearly impossible to get precise readings from it. If the gauge were 3x wider then maybe, LOL.

It's fine for approximate readings but most of the time that's not going to do.
 
From my experience, I use my HV probe maybe once or twice a year. I still consider it a crucial piece of test equipment.

Conversely, I use my scopes, logic probe and digital voltmeters all the time. Same with my soldering iron (and soldapult). LOL - and my microscope!! I really luv my microscope.

If you watch repair vids, especially Brian's, you'll realize how important a Fluke 9010A is. Similarly, I like my CATBOX. And sometimes I use a signature analyzer. My NEOLOCH Inquisitor is great for testing ICs, as are my ABI digi and analog IC testers.
The HP comparator is OK. Lots of test-bench power supplies. I also have electronic load for testing ARII and other power source etc. Gotta have SuperGun too.

What's my point? You can't cheap out on good test equipment, and seemingly, you cannot have enough test equipment. :001_sbiggrin:

Conversely, I have a Fluke 9010 and never use it. I do most of my PCB repairs with a $20 logic probe w audio, and occasionally my HP signature analyzer. I do most troubleshooting on the bench, just powering the game logic with +5V, then test the rest of the functions in the cabs I have (using the scope on occasion to track down analog vector section issues).

I do use my HV probe frequently, but I do a lot of monitor work. And I use it with a cheapo $20 DMM that works just as well as the two Flukes I have, as I compared it. I like having many cheap DMM's strewn about, and dedicate them to specific purposes/places in my setups, so I always have one handy and don't have to go looking for one. Also, DMM's often have little quirks and features that differ between meters, and some things are nicer in certain situations (e.g., and on/off button vs the twist-to-power-on selector switch, or a backlight, or beep features, etc). I have yet to find one DMM that has everything I personally like, but I like having many of them anyway, so I get the best of both.

I don't use a chip tester, but I have an Asteroids PCB that is heavily socketed, which I will use to confirm bad chips on occassion, though I rarely do that, as I can verify they are bad using the board I'm repairing most of the time (e.g., if you replace a chip and it doesn't change the behavior of the board in a way that you can observe with your logic probe or eyes, it was most likely not bad.)

So to the converse point, equipment is never a substitute for experience and technique. My path has always been to have just less than the equipment you need (and work your way up to it, knowing that you really need it), rather than spend tons of money up front on stuff you won't need or use. You'll develop better debugging skills and a better intuitive knowledge of the boards you're repairing if you start with simpler tools, IMO.

Note that VC's and my opinions are more the two ends of a spectrum. Your truth likely lies somewhere inbetween.

Well said by by two pillars of the community, and I agree - with both! I am in that middle ground.

A good, reliable DMM is a must for verifying voltages, resistance, capacitance, and continuity. Some can do even more. It may be the most important tool to spend a little more on to get one that you know you can trust.

I use my trusty Elenco LP-560 logic probe a lot, and in fact at $20 I bought two since it is sometimes helpful to probe two pins at once - for example to see if an output and its inverted output are actually inverted. But not often. For that I'd turn to my scope that includes a logic analyzer, or the HP comparator. The comparator is limited to 16 pin devices, although there is a 20-channel version and cards. Even that cannot do tri-state devices like buffers, so it has its limitations. There are devices to test a chip without removing it but they get pricey and are hard to come by.

I have a Fluke 9010A and use it quite a bit to verify RAM and ROM in situ. I have written scripts for various boards that make use of the 9010 probe to test address decoders and other parts of the board. I enjoy writing the scripts and there is a fair amount of documentation about that and the unit in general. That said, I'm not sure if I could bite the financial bullet to acquire the mainframe and pods at current prices. Luckily I got mine years ago.

Same goes for a signature analyzer. It is good for times when there is no clear starting point to troubleshoot a circuit that feeds back onto itself. For example, if the RAM and ROM and CPU and clock are all good, but a program still refuses to run and there are no stuck pins (or maybe they are stuck because it's not running yet) using signatures can help locate the fault. But that only works on boards for which there are documented signatures.

Sometimes the best you can do is narrow down the suspects, by using an understanding of how the chips and different sections of the PCB are supposed to operate and interact. It's a mix of past repair experience, deductive reasoning based on observed behavior and reactions, chips that seem to fail more than others, as well as research of other people's repair logs. It's also a mix of how much time and effort you want to invest to learn about repair technique and that particular board versus just getting it fixed by brute force replacement ('shotgun').

If you are going to remove a chip, a good desoldering station is important. It is possible to use a solder sucker and/or braid, but it is harder and takes longer, and does more damage to the board. It may seem extravagant to spend a few hundred... until you use one. Once a chip is removed it is much easier to test. My TopMax EPROM programmer can also test a range of chips, while Andy's method of putting a chip in a socket of a known-good board is real-world verification at its best.

I have gone through a few scopes, and currently use a Tek 2247A for analog purposes and recently splurged on a Rigol MSO2202A digital scope with logic analyzer. The first ones were cheaper, older scopes that served their purpose (provide information without too much capital investment) but as I learned more and was able to make use of more features, I could justify paying for a better scope. The ones I have now have more features, are newer and more reliable, but more expensive. One piece of advice for the current range digital scopes is to consider not only features and price, but also the user interface and manufacturer support. The interweb will have reviews that address those topics.

An HV probe is not too expensive. If you only need on occasionally perhaps you can borrow one. If you are doing more of your own monitor work or have a growing number of games, then the expense becomes easier to justify.
 
I use the BK HV-44. I actually have two of them. One was NOS and I got it for around $50, the other one was used for $30. They do the job just fine.
 
I use the BK HV-44. I actually have two of them. One was NOS and I got it for around $50, the other one was used for $30. They do the job just fine.

Arc, do you set your monitor's HV with it? How do you get any precision at all since the gauge is tiny? I'd think you could be off 1000v with it.
 
I have this one :

https://www.ebay.com/itm/BK-Preciison-Model-HV-44-High-Voltage-Prove-Meter-with-Case-/371719592268

I set the B+ and then check it with the probe. Doesn't seem like an issue to me.

Does the face look like this?

1" of meter covers about 33,000 volts. I could see getting to about 1000v resolution with the meter assuming it's really accurate. Is that good enough?

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Does the face look like this?

1" of meter covers about 33,000 volts. I could see getting to about 1000v resolution with the meter assuming it's really accurate. Is that good enough?



It might be 'good enough' to get by in many cases, but having a digital readout is more accurate. Monitors will still 'work' with the HV anywhere in a wide range around the recommended setting. You can be off my several kV, and still get an image (and in some cases, x-rays too). But to dial it in accurately (and to make accurate measurements, e.g., to see how much a monitor drifts as it warms up, etc.) you want digital.

For example, the recommended HV level for a 6100 is 19.5kV. You aren't going to get two decimal places of accuracy with an analog meter. When I rebuild 6100's, I set the HV to about 18.9kV, as they tend to drift about half a kV upwards as they warm up, and I watch them do it, to be sure they're working 100% as expected. I like having that extra level of precision, as it gives me more information.

Not to mention, analog meter movements are more fragile, and dropping them can affect their accuracy, etc. Better tech exists in this case, why not use it.
 
Personally, I would NEVER use a digital high voltage probe. They react too slowly in case there is a problem. I use only ANALOG high voltage probes. I watch how quickly the needle rises as I power up a monitor. If the needle quickly rises and if it gets close to or over the red line, I shut off the monitor immediately to prevent damage to the monitor.

Here is a good analog probe:

https://www.ebay.com/itm/Pomona-Ele...epid=4009844735&hash=item4d7cb7fcf3:rk:1:pf:0

I want to point out that Ken is making a good point. And maybe it's not as understood by the younger generation. Digital is "easier" to read the display, it also appears to be fast, but what Ken is talking about is if there are voltage spikes occurring at rapid intervals your digital meter won't accurately display those. All you will see is a blur of the digital characters until the voltage settles and the meter will then display that voltage. With an analog meter, you can get a better sense of what the voltage transient looks like.

For beginners and for most applications digital is fine, and you can usually just determine that there is a problem, using the digital meter, and swap out the part. Old timers who were troubleshooting prior to the digital meters coming out, know you can sometimes find spikes that you can't see on a digital meter. I say old timer's, but this should be taught in colleges when getting an electronics degree, at least I was.

Yes you can get out your digital scope and watch signals too, but again digital has it's shortfalls. I have an older Fluke PM3394 (Technically a Phillips made scope) that runs in both digital and analog mode. When I was getting my electronics training back in the early 90's I was shown that digital meters, and scope's, can suffer from "digital aliasing". This has come in handy for me when checking the clock circuits on boards. Not everybody needs that type of toubleshooting power on their workbench, but analog is sometimes good to have around to check against digital.
 
Yes..........................................................

Arc (and everyone else), since we can all check and adjust the B+, how necessary is it to really be checking the HV? How well do they correlate?
 
Arc (and everyone else), since we can all check and adjust the B+, how necessary is it to really be checking the HV? How well do they correlate?


If you want to be accurate (and do it properly), measure the HV directly.

Speaking for 6100's (and the other vectors, for that matter), I know from measurement that you can be off by many hundreds of kV (if not 1kV or more in extreme cases) by measuring just the B+. The B+ only tells you secondarily what is going on in the HV system. It doesn't account for variation in the associated HVT circuitry, or the HV transformer itself. Everything has a tolerance.

I calibrate all 6100 HV's I rebuild using my Fluke 80k-40. I also measure the B+, after I set the HV, as I've wanted to get a feel for how much they vary. I've seen the B+ be as low as ~175 and as high as ~188, in order to get 19.5kV at the anode. If you just set it to 180, you really don't know how far off you are.

Again, in many cases it may be possible to 'get away with it'. But it takes the same amount of effort to do it right (and be 100% sure) than to not do it right. So why not just do it right.

Also, safety. For monitors that run at 18kV+ (basically everything except b/w vectors), you want to make sure you aren't too high, as once you get to 25kV or so, you're in the x-ray danger zone.

I had one case of a 6100 that instantly shot to 30kV when I powered it on (as I watch the HV when I apply power for the first time, and yes I use a digital DMM). It turns out there was a broken/cracked trace on one of the pins of the flyback. If I hadn't been measuring the HV directly, I might not have noticed it as quickly.

When working with electricity, a good general rule is to never assume anything, and always measure measure, measure. The times you don't are the times that screw you.
 
Arc (and everyone else), since we can all check and adjust the B+, how necessary is it to really be checking the HV? How well do they correlate?

If everything is working properly, adjusting the B+ to the accepted value will result in HV that is near the accepted value.

If everything is working properly, HV that is too high will be cut off by the X ray protection circuit.

If.

The HV probe is cheap insurance against damaging your chassis, tube, or yourself.
 
If everything is working properly, HV that is too high will be cut off by the X ray protection circuit.


Minor nit (as I agree with your overall comment, and I know you already know this). But for the benefit of others, if we're talking about a 6100, this assumes that 1) you have the version of the HV cage that *has* the HV overvoltage cutoff circuit (as only the later rev ones do), and 2) the cutoff level is actually calibrated properly (which ironically you must do manually, and requires you to measure the HV in order to calibrate it correctly).

Many of the HV cages I see just have the cutoff set wrong or to max (presumably because the previous person lacked the ability to calibrate it correctly, so they just set it to max, effectively disabling it). And when it's set to max, it still can put out ~25kV or more.

Also, #2 applies equally to Amplifones. (#1 doesn't, as all Amp HV's have the HV overvoltage circuit. But the cutoff level still needs to be manually set like the 6100's, which requires an HV probe.) The whole HV cutoff feature in vectors is somewhat of a joke/kludge IMO (which I've theorized Atari only added to appease the FCC), and you can only trust it if you've calibrated it yourself, so it's only marginally useful.

So again, this all falls under the category of 'don't assume anything/better safe than sorry'.
 
If everything is working properly, adjusting the B+ to the accepted value will result in HV that is near the accepted value.

If everything is working properly, HV that is too high will be cut off by the X ray protection circuit.

If.

The HV probe is cheap insurance against damaging your chassis, tube, or yourself.

This.

We aren't flying to the moon with these units.

If anyone is more worried about their HV being within aircraft tolerances than what their cholesterol, blood sugar levels or blood pressure are they need to re-prioritize things a bit.
 
Maybe he doesn't mean what you think he means. But because you like to split hairs ok...

I was referring to what he said about if the B+ is correct then chances are the HV is correct too.

His last part is also correct. The HV probe is cheap insurance. It doesn't mean you need to spend hundreds on a digital one to be within 1 bazillionth of a percent.

My opinion of cheap insurance is the BK HV-44. It's cheap and will make sure you aren't being x-rayed while playing your favorite game. That's good enough for me and should be good enough for anyone unless you really just like to spend money.
 
Maybe he doesn't mean what you think he means. But because you like to split hairs ok...

I was referring to what he said about if the B+ is correct then chances are the HV is correct too.

His last part is also correct. The HV probe is cheap insurance. It doesn't mean you need to spend hundreds on a digital one to be within 1 bazillionth of a percent.

My opinion of cheap insurance is the BK HV-44. It's cheap and will make sure you aren't being x-rayed while playing your favorite game. That's good enough for me and should be good enough for anyone unless you really just like to spend money.


You call it splitting hairs. I call it understanding. The point of the post was the 'if', and that you shouldn't go by just the B+ alone (which was demogo's question he was answering).

Also, a used Fluke 80k-40 isn't 'hundreds'. They're 50-80 bucks used on ebay, and can be used with the DMM you'll already have.
 
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