Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- TekScopes
- Messages
Search
|
Re: Tek 465 no display
Hi Russ,
toggle quoted message
Show quoted text
I won't be any help beyond this point since I never owned a 465 or 468. Do you have a way to measure the AC current drawn on the power line with a Multimeter when you turn power on. If it is zero then the problem is affecting the entire scope and may be relatively easy to find (blown mains fuse, bad on off switch, etc) but if there is some current draw and the CRT filament is not glowing then there would be some current drawn by the rest of the scope and that would suggest either a bad CRT or bad HV going to the CRT. Dennis Tillman W7PF -----Original Message----- -- Dennis Tillman W7PF TekScopes Moderator |
|
Re: Tek 465 no display
On Tue, Jun 19, 2018 at 05:52 pm, <musicamex@...> wrote:
Start with checking the LV test points. Of course after you are sure you have the controls set up correctly. HV relies on the LV being correct. |
|
Re: 465 bad rise time
I'm calling it close enough. The previous owner had turned every var/cap/resistor available and he may sneak into your lab and turn your too. Lock your doors.
toggle quoted message
Show quoted text
/g/TekScopes/photo/59361/3?p=Name,,,20,1,0,0 Hey guys. I have done a lot of work to this 465. I had initially planned on selling it to help me buy some plugins for my 7633. I decided I don't want to sell it and am keeping it. Today I checked its rise time with a pg506 fast rise. Both channel 1 and 2 closely resemble each other and they are not close to right. Before I start trying to calibrate this thing, does it look like there is some type of component issue left to fix? I am thinking since both channels are so alike there is something wrong besides just out of calibration. Raymond Domp Frank Jun 18 #148963 On Mon, Jun 18, 2018 at 05:06 am, lop pol wrote:
Seeing that are both channels are essentially the same just seems weird to me. The vertical output Amp and some other parts, like parts of the channel switch, are common. Raymond You have the proper fast rise generator to perform an adjustment. The risk in my opinion is that you destroy a stuck trimcap or trimpot. You might first verify DC levels in the output amplifier stages and perhaps symmetry in the push-pull signals. Often some stages are common-base current driven which makes it more difficult to check signals. Unlike some other manuals the 465 manuals do not tell which part of the curve is affected by each adjustment. Which version output amplifier is in your 465, discrete or IC? It seems you use the pre-B250000 manual because of what you said about the 10X magnifier. The B250000-up manual clearly mentions the 10X mag. That manual also shows both versions output amplifier. |
|
Re: CRT in Tek 2235
tom jobe
One other thing I failed to mention about your situation, is that people will suggest that you use the CRT out of a 465 or 475 in your 2235.
toggle quoted message
Show quoted text
Will this CRT swap work, Yes... Is it a decent substitution, NO! This CRT swap is a large step backwards in my opinion, and I have done it. tom jobe... On 6/19/2018 6:05 PM, tom wrote:
Hi George, |
|
Re: CRT in Tek 2235
tom jobe
Hi George,
toggle quoted message
Show quoted text
That CRT is not all that rare as it came in many models of the 22xx series. A few common models that also used it are the 2213A, 2215A as well as your 2235 and the 2236. You can download free manuals of lower quality for many of the 22xx scopes, to see what part number they used. The CRT uses a component number such as V9870 and may appear with the A6 parts in the listings, or at the end of the electrical parts listings. As I remember... the CRT for the 2235A and the 2236A is part number 154-0861-10, which seems close enough, but the HV lead to the CRT is enough shorter that it will not work without an HV extender of some sort. They re-arranged the HV multiplier setup on the mainboard of the 2235A and the 2236A to use a shorter HV lead. You want a -00 CRT for your 2235. Other scopes that seem like they should use the same CRT part number are the plain 2213 and 2215, but they are both much different. There are lots of "parts only" scopes for sale on eBay and elsewhere, and you can often buy one of them for not much money, especially if it is located close enough to you to avoid the shipping charges. I think Sphere in Canada sells that CRT for about $85 plus shipping when they have them in stock, to give you some idea of it's fair worth in US dollars. The 2235 is a fine scope, and the easiest to work on of all the Tektronix gear I have ever encountered. It and its peers (from 2213A to 2236) were made in such large numbers that there is a substantial body of knowledge about it, what it's common old age ailments are, etc, etc. tom jobe... On 6/19/2018 9:27 AM, georgeK KB1HFT wrote:
I understand that the Tek2235 wants a 154-0861-00 CRT, which seems to be made of Unobtanium. |
|
Re: Tek 465 no display
Thank you for your reply, Dennis. Unless this is radically different from the 468 re initial control settings, I cant get ANYTHING to appear on the screen..... I think the CRT is not "lighting up". There is no filament glow in the tube (observed through the slot in the tubes metal shield), and the beam finder does nothing. Compared to the 468 the CRT seems to be "off or out of the circuit" ie not getting filament voltage and or HV.
I looked more into the fan control and it appears to be temp controlled, so off when the unit is first turned on? Even with the power on switch "on" and the indicator light showing power on, the fan still never comes on for say 30 min. I have not tested it longer than that. In the download of the manual, i didnt find FIRST TIME USE, but it seemed pretty similar to my 468 and other Tek operational tutorials. Russ |
|
Re: Tek 465 no display
Hi Russ,
toggle quoted message
Show quoted text
Welcome to the group. The best way to do this would be for you to download the manual for this scope from this web page Then read the chapter on "First Time Use". That will explain the purpose of each knob and explain how to set each one for first time use. Dennis Tillman W7PF -----Original Message----- -- Dennis Tillman W7PF TekScopes Moderator |
|
Tek 465 no display
Hi, I am a music teacher in Mexico to help keep kids here. I also teach how to repair and build musicians gear including tube amps. I recently acquired a Tek 465 donated to the program. There is no screen display and despite the 2 fuses are good and the power switch on light does show power is getting to at least part of the scope.
I am not in the same league as most on this site. The 465 makes an average tube amp look like a lightbulb by comparison. I downloaded the 465 manual and service manual but really would appreciate a little step by step troubleshooting help. I always suspect electrolytic capacitors over 10 yrs old and read that the tantalum caps are also unreliable. The boards look like the New Mexico balloon fest in places, so, where to start? The fuse inside the 465 tests 24.5 V on both sides of the fuse, but i couldnt find a diagram with test point values. Also it doesn't appear that the filament in the CRT is lit and the fan doesn't activate when the power switch is turned on like with my TEK 468. The 465 looks like it wasn't abused and has an IBM sticker on it. It looks like one of the filter caps was replaced as it has a blue plastic cover unlike the adjacent aluminum can caps. I haven't disassembled or unsoldered ANYTHING yet. I understand that the 465 is one of the holy grail TEK scopes and i think it might outlast me if I can get it working again. Would someone please walk me through getting the display to come on? The main thing we currently use oscilloscopes for is to track a frequency generator audio signal through a tube amp, looking for a distorted sine wave to help isolate where the problem(s) are. So highly accurate calibration isn't necessary if there is a good clean sine wave when connected to the wave gen. Thank you in advance, Russ |
|
Re: Tektronix 453 Power Indicator Bulb needed
The problem with replacing the small light bulbs with LEDs is that one is almost never a drop-in replacement. You can do it, but have to make some changes to accommodate the differences in supply voltage/current source, AC vs DC, variableness, mechanical fit and mounting, wiring, and light pattern, for example. It's often just easier and simpler to put in new bulbs and be done with it, even though more technically advanced, permanent solutions are available.
I once made an LED graticule illumination assembly to try out in 7K scopes. I found some sort of omni-directional "white" LEDs from a light string, and tacked them into bases from some burned out bulbs, so they could socket the same way, on the original circuit board. I made some simple mods to the driving circuits, and it lit up nicely, with variable and everything. It was hard to tell they weren't the original bulbs in there. Then I tried a screen shot with a digital camera. The resulting pictures showed the traces OK, but hardly any illumination - the LED's whitish phosphor spectrum was not aligned with the camera's response, so even though it was OK visually, it didn't technically work for a common application. Sometimes the particulars of the LED color matter. For just visual lighting or indicating, this would not be a big deal. Ed |
|
Re: Self Governance of TekScopes.
As Dennis said, the "elders" (should) generally provide enough negative feedback - remember, it's a control system keeping the output near a setpoint - that serious moderating shouldn't be required. Off-topics can be interesting and informative, but it usually becomes clear to most of us when something's gone too far out, or too far along, so should fade away. Subtle hints or explicit statements usually suffice, but sometimes some people don't know when to quit, or haven't looked at enough of a thread to see the flow and feedback, and realize it's time to end. Then the "let's wrap this up already" feedback has to get more intense. It's totally at Dennis's discretion to intercede and shut down any conversation at any point, but he shouldn't have to, if we all act rationally, pay attention to the feedback, and think about the appropriateness of what we plan to say.
Ed |
|
Re: Tektronix 453 Power Indicator Bulb needed
At 01:40 PM 6/19/2018, Rolynn wrote:
A 386 lamp has a MTBF of 15,000 or 40,000 hours depending on what data sheet you look at.I have owned my 453 for about twenty years, and have lost track of the number of hours that I've used it. I have never had to replace a lamp. Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA |
|
Re: Tektronix 453 Power Indicator Bulb needed
At 11:33 AM 6/19/2018, Toby wrote:
I get that, but the lamp is still a consumable that will wear out again. How much extra work would a LED specifically be?I value what I do to my own electronics in terms of my bench labor rate. What the LED conversion would cost in terms of my shop labor rate would probably pay for replacing the lamp several times over. People who work on electronics for a hobby, rather than for a living as I do, may value their shop time differently. Dale H. Cook, Radio Contract Engineer, Roanoke/Lynchburg, VA |
|
Re: Tek push-button lettering using pressing iron transfer of laser printed text on non-sticking paper
There's a kit out there to make your own dry transfer decals. It gets
toggle quoted message
Show quoted text
fairly involved, but I used it to make some labels for a 465 I was restoring. It worked fairly well, but it was such trouble that I tracked down an ALPS printer to make decals. Making black legends is trivial compared to making replacement white legends. I think the ALPS printer is the only way to do that for mere mortals except for screen printing. Paul On Tue, Jun 19, 2018 at 12:39:20PM -0700, thespin@... wrote:
I have an ALPS MD1000 I have dedicated to decals. I might buy some water slide decal paper and try this for the cal button on my 576 curve tracer. --
Paul Amaranth, GCIH | Rochester MI, USA Aurora Group, Inc. | Security, Systems & Software paul@... | Unix & Windows |
|
Re: Tek push-button lettering using pressing iron transfer of laser printed text on non-sticking paper
I think you can buy protective lacquer that will not cause the printing to bloom or smudge. Scotch Magic Tape is pretty tough but I wonder of the lacquer is better. I've used ink jet decal material to make new labels for a J-36 bug key made by Lionel. The original labels were made of cellulose and are usually shrunken and disintegrating, if they are there at all. I used a lacquer I bought were I got the decal paper. Put the decals on a piece of white plastic sheet and coated them. This was several years ago, they look original and have not degraded. However, they are not touched constantly like a key top.
toggle quoted message
Show quoted text
On 6/19/2018 12:17 PM, Reed Dickinson wrote:
Hi Gang: --
Richard Knoppow dickburk@... WB6KBL |
|
Re: Tek push-button lettering using pressing iron transfer of laser printed text on non-sticking paper
Hi Gang:
I generated script on my computer that most closely matched the script on the 485's I work on then print the result on laser approved decal paper. I run the paper through the laser printer several times to ensure adequate fusing. The paper is available at Kinkos, Office Depot or other suppliers. I use the kind that transfers when wet. I cover the tops of the decals on the buttons with Scotch tape and carefully trim the edges with a sharp scalpel after the decal is fully dry. Reed Dickinson reed714@... |
|
Re: Tektronix 453 Power Indicator Bulb needed
On 2018-06-19 1:40 PM, ROLYNN PRECHTL K7DFW wrote:
You do make an excellent point, although I expect they are somewhat moreI get that, but the lamp is still a consumable that will wear out again. sensitive to environmental conditions, temp, vibration, shock and so on. That said I'm not planning on operating mine on an active volcano either. --Toby
|
|
Re: 576 Curve Tracer: Trace moving off screen and jittering when pressing CAL/Zero
Craig Sawyers
That is exactly what I did with mine, pretty much to the letter. Glad that it worked for you too.
toggle quoted message
Show quoted text
Craig I removed some circuit boards to get access to the switch board. I then took a syringe with a curved |
Ancel
Dale H. Cook
to navigate to use esc to dismiss