HITACHI V-353F OSCILLOSCOPE V-353-F

A friend of mine sent me a rather cryptic message. Apparently he's got one of these scopes that's decided it doesn't have to do what its supposed to.

Not reading anything on the inputs Then it will loose one channel

I guess for a start got a link for the manual?

--
"I am a river to my people." 
Jeff-1.0 
 Click to see the full signature
Reply to
Fox's Mercantile
Loading thread data ...

I had a related scope -- V152F -- and they are not very capable nor fast. Triggering is pretty good for the era. Really probably not worth putting any time or money into.

Reply to
Terry Schwartz

On 3/16/18 7:27 PM, Terry Schwartz wrote: > I had a related scope -- V152F -- and they are not very > capable nor fast. Triggering is pretty good for the era. > Really probably not worth putting any time or money into.

It was a request from a friend of mine, Peter, in Australia. The scope belongs to his friend Phil.

I just got off of Skype with them a few minutes ago.

Apparently Channel 1 died about 4 years ago, and recently Channel 2 died.

Phil says it's his only scope, so he's sort of dead in the water right now.

--
"I am a river to my people." 
Jeff-1.0 
 Click to see the full signature
Reply to
Fox's Mercantile

Channel 2 died. "

Shame, if you would have worked on it then you would have a good channel for comparison. Like in a stereo, using one channel as the reference for the other.

Couldn't find a print on it.

What do you mean died ? Did the trace stop moving or did it disappear ? If it disappeared the first thing to look at it the voltage on the deflection plates. If they are equal look to the blanking circuit.

This is not going to be easy without service information.

Reply to
jurb6006

No response to vertical input.

Both traces are present, position works, sweep varies etc.

It just acts as if you weren't plugged into the input.

--
"I am a river to my people." 
Jeff-1.0 
 Click to see the full signature
Reply to
Fox's Mercantile

So, how much did this piece of crap cost new? And how many hours did you waste "fixing" it?

:-)

Reply to
Terry Schwartz

Bwahahaha, It's not mine, and so far, I'm into it about 10 minutes. It's in Australia so I don't have to work on it.

--
"I am a river to my people." 
Jeff-1.0 
 Click to see the full signature
Reply to
Fox's Mercantile

etc. "

Excellent, now we can go from there. I am not an expert in scopes but I am, or at least was an expert troubleshooter.

Each trace is controlled by the proper position control without abnormal in teraction between the two. It shows both traces simultaneously in chop or a lternate. If this is all true that means the output and the channel switchi ng circuits are working properly.

One question, relevant but not of prime importance, does you friend always use the X10 probe ? ALWAYS use the X10 probe unless you need the gain affor ded by the X1 probe. this protects the front end of the scope and lowers ci rcuit loading during testing. Since he cannot fix it himself he might not k now this. Ask and tell when you get the chance. There is a chance that he a ctually caused the failure if the one channel in the past and then this cha nnel now if he does not use the X10 probe(s).

Regardless we still have a direction. there is a slight difference though, if he used the X10 all the time we are looking for a fault that just happen ed, if he uses the X1 we might be looking at something else. But that does not stop us in our tracks.

You are going to need, at minimum a signal generator or a working scope to fix this. If DC voltages would reveal the problem most likely the trace wou ld be off the screen on affected channel(s). Since it is not we are dealing with a dynamic situation, not a static one.

The attenuator is not likely to develop a fault that would cause no respons e in any range, before it is suspect as is after. There is nothing active b efore the attenuator except the AC/DC switch which is easily tested. Then w e have the possibility of him causing a low value resistor there to open ei ther by excessive slewing in the input signal or overvoltage slamming again st clamping diodes. That is eliminated with a signal generator. It is all h igh impedance so take a generator trough a 2K resistor to the portions of t he switch and see if you get deflection. If so it is right up front, if not , it is after the attenuator. A 1 KHz square wave is usually sufficient. Ab out 10 volts P-P should get a rise out of it. If it is extremely distorted though it is still after the attenuator.

Then you need to find where the signal goes. If it is single sided PCB it i s not all that hard. Point to point and multilayer PCBs bring in magnitudes of increased difficulty. But you can still look for identical components.

Being Hitachi and not HP or Tak is actually an advantage here. It is likely that the parts are not house markeds and thus can be researched. Like to g et the pinouts of ICs and the specs on transistors. And being Japanese, or at least conforming to their standard rather than JEDEC or whatever, on tra nsistors the collector is usually in the middle. It is much eeasier to dete rmone of it is BCE or ECB than the US way. Actuially some European standard s are like those of the US, but Hitachi is usually going to be BCE or ECB, unless it is a really high frequency transistor in which case it could be B EC or CEB. If it is like a 20 MHz scope or so you can almost count on it be ing BCE or ECB. Too bad don' t remember my login for Hitachi from my workin g days. If I find it I will get the print and somehow supply it, though I h ave no hosting right now. Maybe I could email it to someone who does or per haps contribute it to BAMA or some other free file place.

But for now we must do without.

So now, look for the switching circuit as well, it will have at least 4 dio des per channel, high speed and it will be directly before the main vertica l output amp. the generator with the resistor may help. Always use the resi stor because otherwise you might cause further problems. And be on the look out for a very small result on the screen because some of the stages might be mainly current driven. that means low impedance. just be attentive.

Get back here with a list of equipment you can use on this in the way of ge nerators and working scopes and either their specs or model numbers. Don't reply via email. Put it out here so we can get input from others or perhaps help someone. I avoid doing this by email for those reasons. In fact I che ck this group more...

I will watch for your response.The 2K value for the resistor is not etched in stone, 1K would do but... and 5K would do but...

Just find out what you can.

Reply to
jurb6006

Oh, you are ot going to be able to do this yourself ? i forgot that part. It looks like your friend is in for some work and education. just forward all this to him and get his responses or whatever.

How else would it get done ?

Reply to
jurb6006

Last but not least, those who say it is not worth your time, fukum. (well n ot really)

They have no idea what your time is worth to you.

They have no idea what your friendship is worth to you.

They have no idea what new knowledge and techniques are worth to you.

And, analog scopes are "the bomb" in contemporary vernacular. As you teach with one you slow down the sweep so they can actually see the trace move as you connect a battery, or a speaker output from an amp. I think the study of analog scopes should be mandatory in schools at least in the beginning w hen they learn the basics. If you can rig up simultaneous voltage and curre nt sensing you can demonstrate reactance, power factor and all kinds of shi t in real time. You can make them understand for real rather than just able to do the math. The young need this knowledge for all that is to come, and there is no better way to instill it. I will try to save almost any DC cap able scope that has triggered sweep and a decent graticule.

Reply to
jurb6006

Phil and his scope are in New South Wales Australia. Most decidedly NOT on my bench.

I forwarded you full response to Phil.

--
"I am a river to my people." 
Jeff-1.0 
 Click to see the full signature
Reply to
Fox's Mercantile

Not to impugn your friend's intelligence Jeff, but any chance he first had one and now two broken probes? Most of us would assume he'd try to swap probes after the first channel went out but...

Reply to
John-Del

Impugn all you want, you are right. It is possible he only has two probes.

Getting this down Fox's ? Stick something in the hole in the BNC connector on the scope and see if you get anything out of it. Sorry, I assume things like this have been eliminated but I have been burned a few times.

A thin gauge wire on a resistor or cap will fit in there. If this has already been checked - disregard.

Reply to
jurb6006

They had the scope turned on while I was talking with them.

No response to anything on the input BNC connectors. However, the vertical would "thicken" in response to the cell phone transmitting it it was close enough to the scope.

I'll say it again, it looks like they killed something between the input connector and the vertical amplifiers.

--
"I am a river to my people." 
Jeff-1.0 
 Click to see the full signature
Reply to
Fox's Mercantile

I love when someone declares himself an "expert".

I've been in this field 40+ years and I learn something every day I work on electronics.

I hope I am never so pompous as to consider myself an "expert".

Reply to
Terry Schwartz

You probably are an expert. There is nothing that says that experts do not continue to learn, in fact, quite the contrary.

No need for excessive humility, you got bona fides then let it be known. I have done things that would blow most peoples' minds, want a listing of some of them ? You probably have as well, that might make a good thread actually, the unusual.

Reply to
jurb6006

transmitting it it was close enough to the scope"

Next question; does the amount of thickening (amplitude) change with the setting of the volts/div ?

Reply to
jurb6006

not really)

h with one you slow down the sweep so they can actually see the trace move as you connect a battery, or a speaker output from an amp. I think the stud y of analog scopes should be mandatory in schools at least in the beginning when they learn the basics. If you can rig up simultaneous voltage and cur rent sensing you can demonstrate reactance, power factor and all kinds of s hit in real time. You can make them understand for real rather than just ab le to do the math. The young need this knowledge for all that is to come, a nd there is no better way to instill it. I will try to save almost any DC c apable scope that has triggered sweep and a decent graticule.

oo much. ISTR they had 2 line speeds, nothing more than a pot to select vertical sen sitivity, no graticule & plenty of distortion on a 2 or 3" round CRT etc. A s basic as it gets.

NT

Reply to
tabbypurr

You have to wonder what would happen to it if a bunch of water from the second floor dripped down on it.

Reply to
bruce2bowser

That seems unlikely, since they are "down under". Everything is backwards there -- water drips UP from the basement to the upper floors.

Reply to
Terry Schwartz

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.