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Typo - sorry about this
Should be:

Where would you want a thick film, or a Ceramic, or a carbon film resistor?

Jon,

Thanks for the recommendation! I found it and looking at it now.

Barry

Roy,

I'm not going to blow my own horn here, as I do this primarily as a service to fellow Tek owners.
There are hundreds of members here who have bought my kits, who can speak for me if they wish.

Sure you can spend hours of your own time, poring through pages of Digikey and Mouser parts, and make up your own selection.
That's your privilege, and nobody can take that from you.
But do you really know your scope's circuits and functions so intimately, that you can easily select which components out of a vast pool of available components is really the most suitable, most reliable or longest-lasting one?
Where would you install a super-low ESR capacitor, and where would you install a Low-Dissipation capacitor in the scope?
Where would you want a thick film, or a Ceramic, or a carbon film capacitor?
Do you really want to open up your scope time and again, because your choice of component may not have been the optimal one, even though all on paper, all the numbers matched up?
Do you want a fully-working scope in the minimum possible time, at a fair and reasonably low price, or do you want to troubleshoot part-by-part, hour after hour?

The time which I spend evaluating the photos of the Scope's PCB's including close-up inspection to determine whether additional components are defective, and answering the customers' questions during installation, is certainly not reimbursed in the kit price.

My experienced eye can identify problem components which the owner doesn't even know about.

Some of the components in my kit are not available from Mouser or Digikey, and I source them directly from Vishay's warehouse in Israel, not because it's convenient, but because it's the most optimal part for that circuit.

The bottom line is that it boils down to trust.
My customers trust me that I will deliver the optimal products for a fair price, about which they need have no concerns as to whether the product will provide a successful overhaul, and reliability for decades ahead.

Let me put it this way - if I was in the market for a used scope, and I had to choose between an unknown overhauled scope for which the owner used my kit, versus one which the owner sourced his own parts, there is no doubt that I would want the one which has my components installed. Not because my parts are optimal or better, but because I have no idea what the knowledge level of the other owner is, and what criteria he used to make his selection of components.

This statement is not intended at all to denigrate the abilities of the highly knowledgeable and competent techs on this and other forums, who likely have much more knowledge and experience than me, but only to suggest that it's a good idea to assimilate the experience of "those who have come before you", and not to focus on saving a few pennies here or there.

In 2009, I overhauled my own 2465B with exactly the same components in my kit. It now 16 years later. The scope is on 10-12 hours a day, 6 days a week. That's an easy 50,000 hours. I have had 3 failures in that time, all unrelated to the circuits in which my kit components were installed. They were: the A2 ON-Off switch burnt out - replaced; a diode on the A3 shorted after a power failure - replaced; and the A5 failed (corrosion), with a whole bunch of the SMD ladder resistors and a couple of semiconductors needing replacement - thanks to Siggy for his diagnostic help with that. I expect trouble-free performance for at least another 50,000 hours.

Menahem

For convenience:

/g/TekScopes/photosearch?p=created%2C%2C%2C50%2C1%2C0%2C0&q=tek%20user%20comments

Raymond

Hello Trevor,
Sorry for the late reply.
I would first start with allignment of the 3kHz, 30kHz and 300kHz filters in the VR Module explained in the Service Manual. The trim capacitors get bad contact over time. I've written earlier on this issue. Left click on my name above this message and search for 2712. You will find more info there.
Good luck.
I will be glad helping you futher for as far as I can.
Jaap PA0JRK

I just deleted a message on this thread. If any more divisive messages appear, they will be deleted and the thread will be locked.

David

On Sat, Apr 5, 2025 at 01:33 PM, Jim Ford wrote:

Nope, David, at the risk of getting political
:

IMO... I'm not sure... at this time... expressing political opinions... in the forum... is a good thing.... I mean good for the forum.
I'd like to here more about why people use 'capacitor kits' ... to fix 24XX series scopes, rather than sourcing the parts themselves.
I don't usually replace a component, unless I know it's bad.



--
Roy Thistle

I had always heard that Sony was exceptionally nasty about keeping people from rebuilding their jugs. Either this was not true or there were cracks in the system that allowed some to slip through.

Brenda

Ask ETF, the Early TV Foundation.

The the Trinitron gun was probably old stock horded by someone like me...

Ha!

Frank DuVal

You may have no choice...is you iphone or android containg china components?

The problem is getting replacement electron guns. It is very unlikely anyone in the USA is able or willing to tool up to do this work. I think the only place left that makes television jugs is in India. I am curious where the rebuilders in the video got the replacement gun for the Trinitron jug they rebuilt. There is also the issue of people who can do the work.

? Brenda Gentry, KA2IVY

Does anyone dare to do it with an oscilloscope tube?

Repairing a 7t11 was like decoding alien technology — I needed almost a week just to understand what it was trying to tell me!

Tam

Your video is most entertaining and well explained.
Well done!

The documentation accompanying my kits is spot-on, with all the correct codes and descriptions fully matched, ensuring the fastest possible clearance.

Menahem

I misspoke. It looks that that particular .bin file can't be downloaded for some reason.

Luckily, 160-3493-00 / IC U2400 (I mistyped the p/n in my previous post) is socketed and there no need to desolder. I'm going to remove the IC and clean the IC pins and socket and see if that helps things any. I'll also try to swap the IC from my 2245A if cleaning it doesnt work. If that works, someone from the list has a parts 2246 with the needed IC.

Thanks all!

Hi Vladimir and all

For the purpose of helping others who may have to tackle similar repairs, here is my report:

It should first be noted that there are at least two types of power supplies: an older model using discrete standby circuitry, the schematic being the one mentionned by Vladimir, and a more recent one incorporating an integrated controller, the one I mentionned.

Some photos of the repair can be seen here: /g/TekScopes/album?id=301696

Initial inspection revealed no voltage across the primary capacitor terminals, which required its removal to access the screw securing the bridge rectifier. It's worth mentioning that significant heat is needed to desolder the larger connections; otherwise, there's a risk of damaging the plated through-holes on the PCB. I used a soldering iron set to maximum temperature, in conjunction with a high-performance desoldering tool featuring strong suction. The Tektronix-branded PCB is of high quality and withstands heat very well.

After replacing the bridge rectifier, I observed that the expected 15V rail, generated by the standby supply, was still missing. I replaced the TOP200 controller with a TOP226—a second-generation equivalent from the same manufacturer—which restored the 15V rail, but the main power supply still failed to start.

I spent some time analyzing the protection circuitry. Disconnecting the various protection subsystems one by one did not resolve the issue. The supply remained stuck in a "hiccup" mode—operating for approximately 10 milliseconds once per second. This short active window allowed for probing and measuring voltages on the power rails.

To better monitor system status, I added LED indicators to the control circuitry. The first LED confirmed presence of the 15V standby voltage. A second LED, triggered via a transistor, illuminated when the voltage on pin 10 of the 3525 PWM controller (available at the cathode of CR9 near the top of the A18 board) was high—indicating that either the overvoltage or overcurrent protection had activated, or that the power supply was shut down.

I then cut away the portion of the PCB that had been completely burned beneath capacitors C47 and C83. Unfortunately, several surrounding traces were also affected by the damage and had to be removed and re-routed using insulated Teflon wire.

Once repairs were completed, the LED indicators confirmed that the unit was still operating in hiccup mode. Nonetheless, I was able to take voltage readings during the brief on-times. These preliminary measurements were mostly within expected ranges.

Next, I connected resistive loads to the dual-row headers labeled P5 and P6: 12-ohm, 2-watt resistors for the 5V outputs, 100 ohms for the 15V lines, and 330 ohms for the 24V rail. With these loads in place, the power supply began operating continuously, enabling accurate measurement of output voltages. All outputs were within spec, except the 24V line, which measured 32V. Since the 24V output is unregulated and rated for a nominal 2.5A, I connected an ammeter and a 10-ohm load to draw current. Under load, the voltage dropped to 22.5V, which I deemed acceptable.

To mechanically reinforce the repair, I used silicone adhesive to secure the replacement capacitors to one of the power supply's metal supports.

After reinstalling the unit, I was pleased to find that the device powered on successfully and passed all self-tests.

Jose Luu <jose.luu@...> added the photo album 784A PSU REPAIR ( /g/TekScopes/album?id=301696 ) : images of burnt and repaired area of a 784A PSU

On Sat, Apr 5, 2025 at 05:21 AM, Jay Czaja wrote:

I have a question. What is the best way to measure ripple on the LV supply.
When I checked it the first time, I had the 2247A on an isolation transformer
with my 2245A connected directly to mains AC. I used a x1 probe on my 2245A to
check for ripple and clipped the ground lead of the probe to the chassis of
the 2247A.

No need to use an isolation transformer to float the scope for this measurement. The chassis of the scope is grounded normally, not like old CRT TVs or monitors that mostly had a "hot" chassis.
Just use your other scope, set it to AC coupling and go as low in attenuation to get a readable signal across the power rail being tested. Connect the probe to ground and the tip to the power rail and see how much noise level you measure. You might also want to switch in the 20MHz bandwidth limiter so as to possibly get a more cleaner and relevant display. Ideally use a X10 probe, but X1 should be ok.

On Fri, Apr 4, 2025 at 03:23 PM, Jay Czaja wrote:

I found also this part number 160-2393-00 on the following 2245A "TekWiki"page
and there appears to be a ROM image. Is this something that would be abled to
be downloaded and programed?

You could download that BIN file and program it into a new prom chip. Perhaps the existing one is flaky, hence the come and go error?

This scope has me scratching my head. I had it running all night without any problem, I doubt part number 160-2393-00 is actually the culprit despite the occasional startup error. I suppose I should scrutinize the PSU more.

I have a question. What is the best way to measure ripple on the LV supply. When I checked it the first time, I had the 2247A on an isolation transformer with my 2245A connected directly to mains AC. I used a x1 probe on my 2245A to check for ripple and clipped the ground lead of the probe to the chassis of the 2247A.

Would it be more accurate to connect the probe ground to the ground on the LV test header (J1204) instead of the chassis?