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I had a problem with my 465M that turned out to be C582, so I replaced it and C584 as well. I have another Tek scope that has a very similar HV circuit that kept blowing the equivalent fuse. The transistors equivalent to Q556 and Q553 got rather hot. I wound up replacing all the semiconductors in that entire circuit. and it seems to be happy now.

My PS503 has a couple of OverVoltage SCRs on the +33 and -33 busses effective for S/Ns B022064 and below.
The +/-33V is also used to create regulated +/- 27V in a lot of other plugins, often by a pass transistor mounted in the plug-in, and +/- 5V via Zener but I would doubt it could draw that much current. I think the series resistor for that would limit the current sufficiently.

Hi There,

We have a scope at work with 80SJNB - I'll check to see if I have on CD - however it's pretty old (Windows 98).
Also, you can download 80SJNB for Windows XP scopes from the Tek website.
Which O/S is your scope running?

However, getting the software is just part of your challenge. You will also need a license code -> Google is your friend ;-)

Regards,
- Guy.

On Fri, Apr 30, 2021 at 12:41 PM, Torch wrote:

These are decent probes, good bandwidth, reasonably priced and have the Tek readout pin. 10x only though:

Note that this particular example has a broken cable jacket at each end, which would seem to indicate that the cable had been stressed at those points. That might be okay, or it might be a sign of a problem. The probe tip also appears to be bent; those usually break off when you try to straighten them.

I've had orange lines on a color display when the display is powered up but not initialized properly.? There's supposed to be a clock input to the display.? When it's not correct, the duty cycle on the display LCD can give you that odd looking orange.

How you could get this on a monochrome display I don't know.? I do think that it has to d with bad connections to the display.

Harvey

On Fri, Apr 30, 2021 at 07:01 PM, Pwrelectronics wrote:

What should I look at? After the obvious with bad connections someplace

Does the scope have an optional I/O module e.g. GPIB ?
If so, make sure it is seated as far as it goes. The pins
on the motherboard are very short and if the module doesn't
make good contact on all pins there could be boot problems.
You could also remove the module completely and see if the
problem persists.
/H?kan

Have you followed the oscilloscope repairman's motto? Thou shalt check voltages.

Begin at the beginning. Check the supply rails. If those are good then you can move on to check voltages at major components (like the CPU chip). For something this modern you might not even need a schematic: e.g. the voltage regulators may be pre-packaged parts so you can tell what they're doing just by looking at the part number (or a few components around them). Checking the power supply for the logic chips is as simple as finding an identifiable logic chip and probing its power pin.

The bigger trick may be getting it to perform the malfunction on demand (e.g. with the case off, though this does not sound temperature related).

For a problem like this one, which goes away when physical force is applied, you should suspect a bad solder joint, or something similar. That would actually be a best case outcome, as it would be easy to fix.

Also, it never hurts to do a simple visual inspection of the boards and components. It's unlikely, given your symptoms, but maybe something burned up or spilled its guts.

-- Jeff Dutky

That's what I hate about ebay- pages and pages of sellers trying to sell the identical useless junk from china.? I guess somebody must be buying it.? It's really annoying if the item you're looking for has a very generic name!? Creative search parameters can weed out unwanted listings, but not all the time.? I was looking for something a few weeks ago, and I'd get either 4 hits or over a thousand, depending on how I was searching.? Strangely, there were about 30 items that fit my search and shouldn't have been excluded by the exclusion list, but were anyway.? Never did figure out why.
-Dave

Yes orange lines... When slapped, the screen goes to the normal monochrome white and boot-up messages. The orange lines are in a specific pattern (these are horizontal lines) and it appears the back light is working.

I am presuming that the orange lines are what you get when there is no input to the display board from the motherboard? I am only assuming the issue is with the mother board because it goes to the boot up self test when shocked. If the issue was with the display board, I would expect that it would come up as "normal" with a mechanical shock well after the mother board booted and not see the self test messages at that point.

Good luck. I seem to remember someone sketching the schematic of these
attenuators, where this resistor was in-line with the signal. Presumably
it's for dampening and/or a fusible cutout, and so the power rating
shouldn't be a problem. I don't think the 380 or the 420 have a 50Ohm
coupling option?

On Fri, Apr 30, 2021 at 3:29 PM Richard Peterson <saaber1@...>
wrote:

Thanks Siggi. I found that article and it inspired me to dig into my
repair. Since Mark used an 0603 SMD resistor I assume the power
requirement is pretty low but i thought i'd ask others. I can probably
squeeze a 1206 in there, but it would be much easier scrape away the
remains of the old resistor and solder in a 1/4 watt resistor (or two in
series). I was mostly concerned about the power rating of the original
part, but given the size, I guess it's pretty low. I'll try the metal film
resistors, matched to the value of the resistor in CH2 and see what
happens. Hopefully nothing on the underside of the board is also blown.
I'll post my results . . .

Thanks Siggi. I found that article and it inspired me to dig into my repair. Since Mark used an 0603 SMD resistor I assume the power requirement is pretty low but i thought i'd ask others. I can probably squeeze a 1206 in there, but it would be much easier scrape away the remains of the old resistor and solder in a 1/4 watt resistor (or two in series). I was mostly concerned about the power rating of the original part, but given the size, I guess it's pretty low. I'll try the metal film resistors, matched to the value of the resistor in CH2 and see what happens. Hopefully nothing on the underside of the board is also blown. I'll post my results . . .

On 30. Apr 2021, at 20:20, - <rrrr6789@...> wrote:

Amazon did have an auction service when the first started ....

I also remember that. There have been discussions about Ebay and Amazons bidding system, quite different.

I do not really understand the diiference of "buyers" and "sellers" marketplace. I think it has more to do if you're selling "new" against "used". Many arguments and complaints of buyers are not possible with "new" items. What suits well for used goods does not necessary work well with new, and vice versa. Perhaps Ebay would be better of making their payment conditions depend on the status of what is offered (new/used/broken...).

What I like less about Ebay is its constant ranting about shipping fees, without offering the slightest help. If they rant about shipping fees they should offer a service that consists in picking up the good, then packing and shipping it. If they did that, I would be happy having the money transit through Ebay as well.

cheers
Martin

Very nice, Dennis. Thank you.

DaveD

--
This email has been checked for viruses by Avast antivirus software.

TDS220 isn't colour ... so maybe you are seeing the ccfl? (trying to start, undercurrent?)

Anyway, I have a TDS220 from the dumpster... that probably should have stayed in the dumpster. (They are not really that good of an oscilloscope.)

I haven't posted about mine here. I wasn't sure there was going to be too many people that could help.
Not recommended for long term use... but, what happens if you connect it to a power bar with a switch.... and use the power bar switch to cycle it? (always keeping the on/off button on the top of the scope in the on position [pushed in])

--
Roy Thistle

Thank you Dennis!
-ls-

Amazon did have an auction service when the first started but it
soon became clear that E-bay was going to dominate so Amazon completely
dropped their auction service. But I DO wish that they would reintroduce
it!

Originally Amazon and Ebay were very different and had very diffeent
markets. Amazon started off as just an online, fixed-price retailer with
large volumes of identical new items (originally just books) and they've
since opened up to other sellers of new identical items verses Ebay which
started out as purely an auction service for individuals that wanted to
sell their used items. But E-bay has now shifted their approach and are
trying to also attract retailers with large quantities of new identical
fixed-price items instead of individuals with a single used items.
Unfortunately for many of us, Ebay no longer attracts the sellers of used,
and originally very expensive when new, specialty items that we're looking
for.

On Fri, Apr 30, 2021 at 1:57 PM Roy Thistle <roy.thistle@...>
wrote:

On Fri, Apr 30, 2021 at 07:39 AM, Dennis Tillman W7pF wrote:

It sounds like some of you feel entitled to be treated a certain way by

eBay

There are many on-line marketplaces... Amazon, PayPay Mall, Ebay,
Alibaba(AliExpress, Taobao) Rakuten, and others... but Amazon has about
twice the visits of all the rest put together... while Ebay gets about 1/4
of what Amazon does. Amazon dominates.

One reason why Amazon dominates might be because Amazon was quick to
become a buyer's market, with good support for buyers. Ebay was quite slow
to do that.

Sellers always complain about Ebay, and Ebay buyers: there's enough of it
on TekScopes, and copious threads on Reddit. But then some sellers are
still doing the same things that caused Ebay to become a buyer's market in
the first place.

The OP on this thread was pondering an alternative to Ebay. I reckon, I
don't see one... not with a global reach anyway. It's safe to say, greater
than 99% of the population considers what we have as being junk. Certainly,
the U.S. government... which originally paid for much of what we have
does... and institutions certainly do. Most Ebay competitors don't even
list it. So if Ebay stopped listing surplus, where would you sell?
--
Roy Thistle

TDS220 is monochrome. Orange lines?

RL

Hey Rich,

Matt D'Asaro fixed at least one attenuator in a TDS-420 that was similarly
bad. The article is here:
. The images
don't load for me, but you can still view them at these links:



Good luck,
Siggi

On Fri, Apr 30, 2021 at 8:55 AM Richard Peterson <saaber1@...>
wrote:

Hi Folks. New member, first post . . . I recently picked up a couple of
new to me Tektronix scopes to replace my Hitachi V212. The 2236 is up an
running beautifully after some cleaning, but the TDS380 has a (hopefully)
small issue: No input on CH1. I've traced the problem down to what looks
like a burned 50 ohm thick film resistor on the input of the attenuator
board between the BNC and one of the capacitors on the board. (not quite
sure how to post photos here yet but hopefully this link works:
/g/TekScopes/photo/263498/3215960?p=Created,,,20,2,0,0)

I'm thinking I can simply solder a 50 ohm resistor between the BNC
connector and the SMD capacitor that the original resistor links (the
larger capacitor at the end of the first relay in the photo) . Any
thoughts about doing this and what power rating the resistor should be?

Thanks.

Rich

On Fri, Apr 30, 2021 at 07:39 AM, Dennis Tillman W7pF wrote:

It sounds like some of you feel entitled to be treated a certain way by eBay

There are many on-line marketplaces... Amazon, PayPay Mall, Ebay, Alibaba(AliExpress, Taobao) Rakuten, and others... but Amazon has about twice the visits of all the rest put together... while Ebay gets about 1/4 of what Amazon does. Amazon dominates.

One reason why Amazon dominates might be because Amazon was quick to become a buyer's market, with good support for buyers. Ebay was quite slow to do that.

Sellers always complain about Ebay, and Ebay buyers: there's enough of it on TekScopes, and copious threads on Reddit. But then some sellers are still doing the same things that caused Ebay to become a buyer's market in the first place.

The OP on this thread was pondering an alternative to Ebay. I reckon, I don't see one... not with a global reach anyway. It's safe to say, greater than 99% of the population considers what we have as being junk. Certainly, the U.S. government... which originally paid for much of what we have does... and institutions certainly do. Most Ebay competitors don't even list it. So if Ebay stopped listing surplus, where would you sell?
--
Roy Thistle

I've used Ungar, Hakko (both wand and gun), and Metcal.

I've found the Metcal system to be better, although you do have to make sure (for any of them) that the tip is clean and capable of good heat transfer.

One thing you can do is to use a larger (still controlled!) iron to heat an area, then use the solder sucking tip to vacuum up the solder.

There's only so much heat you can get out of something designed to *not* damage a delicate PC board, when the object needed an industrial soldering iron to heat the surrounding acre of board and part, let alone chassis.

Harvey