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: A sick 465B
Mark,
Thank you for the pointers. I will investigate them all. I was able to get the HV up to -1600 V for a few minutes, which was just long enough to verify that the replacement CRT was working and undamaged. I got to that point by cleaning R1427 with IPA, so it may well be that there is surface contamination providing leakage paths in the HV section. I don¡¯t want to jump to any conclusions, however, since the problem has not been remotely solved. The investigation may take a while because I¡¯ve got other, more pressing issues that require the bench. I¡¯m happy, however, to have addressed one of the big problems with this scope (the CRT damage) though I guess I just replaced it with the HV fault. ¡ª Jeff Dutky |
|
Re: A sick 465B
Jeff,
I will take a few guesses to your problem. See if the 10,000 ohm resistors in the -2450v circuit are high/open, C4006 being bad, the .0068mfd condensers bad in some way leaky or open, the two diodes in the G1 circuit bad (if so, use 1N4937 as replacements or dust making a leakage path or the multiplier is leaky. The 10meg resistor across the 180V zener may be high, if so use a Xicon 273 series. This is another value I keep a stock of. Let us know what you find. My guesses may be wrong. It will not hurt to test them. That will eliminate those as a/the problem. I hope the others are coming along in their restoration. Mark |
|
Re: Tek TDS-3000 V3.41 Firmware
Hi;
There is a thread on EEVBlog about issues with the download. Here is the link along with what should be a good 3.41 package: On Thu, Feb 17, 2022 at 4:46 PM ebrucehunter via groups.io <Brucekareen= [email protected]> wrote: In preparing to update the firmware on my TDS3052 scope to V3.41, I |
|
Re: Type 130 L-C Meter
Jerome,
The 10meg resistors I got from Mouser are 1/2W Xicon 273 series. You may want to get extras in this value for other items. The 1% types have a low temperature coefficient which is better in low level circuits. The 5W I mentioned I got from ebay from China. You can get the 1% types now which I prefer. If you want to add inrush limiting, add a 527-CL70 NTC from the mains to the power transformer. The dual 15mfd in the B+ supply can be a single 33mfd ULD type. R403 can be increased in resistance, e.g. 3300 or 3500 ohms. This reduces the current through the VR tube and keeps the lower B+ stable. I got my 130LC last year after looking for some time. I am glad I got mine and restored it. It is great to use when needed. I am sure you will be happy with yours when you get it going. I am glad to see one of these being brought back to life and used. Mark |
|
Re: Type 130 L-C Meter
Thank you Mark, that is information I can use, along with all the other info I have received from the members here. I really do need to replace the electrolytics. They won't last forever. All the paper types are gone and have film types in their stead.
toggle quoted message
Show quoted text
On 2/17/22 21:12, Mark Vincent wrote:
Jerome, |
|
Re: Type 130 L-C Meter
Jerome,
I have a 130LC I restored. I used 1% resistors except, for now, the 33,000 ohm 5W 5% (I plan to make it a 1% type soon) replacement of R95. It is a bit larger in power than necessary. A 3W would work. It works fine now. I did use Nichicon ULD types for the electrolytics. I did replace the old wax in plastic case with 5% types. The pots for the three ranges may need to be adjusted when the .0047mfd and larger values are replaced on the switch. Mark |
|
Re: Tek TDS-3000 V3.41 Firmware
There were some floppies that did 2.88 MB, but they were very rare.
toggle quoted message
Show quoted text
CD's do 470 mb or so, DVD's do 4.7 GB.? If at all possible, use an SD card or microSD card for cheapest storage. Putting a file on a disk uses up N clusters, where n (typically) is 512 bytes.? If your file is 1 byte over a limit, then it takes another 512 bytes, even though it really doesn't. It occupies that last sector, (or cluster in an HD), but doesn't use all of it. Harvey On 2/17/2022 8:47 PM, Jim Ford wrote:
Bruce, IIRC, a 3.5 inch floppy holds 1.44 MB.? So, yeah, 1.5 MB plus a bit more would probably push it over the edge.? ? ? ? ? ? ?Jim Ford?Sent from my T-Mobile 4G LTE Device |
|
Re: Tek TDS-3000 V3.41 Firmware
Bruce, IIRC, a 3.5 inch floppy holds 1.44 MB.? So, yeah, 1.5 MB plus a bit more would probably push it over the edge.? ? ? ? ? ? ?Jim Ford?Sent from my T-Mobile 4G LTE Device
toggle quoted message
Show quoted text
-------- Original message --------From: "ebrucehunter via groups.io" <Brucekareen@...> Date: 2/17/22 5:11 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] Tek TDS-3000 V3.41 Firmware To follow up on my previous message, I just noticed that when I copied the V3.41 files from my computer to a memory stick, for carrying to my old laptop in the shop, each file was swelled by 20 to 30 kB.? This might have been just enough to put the third group of files beyond the capacity of the disk.Tomorrow I'll try downloading them directly to the old laptop with a 3-1/2-inch drive.Bruce, KG6OJI
|
|
Re: Type 130 L-C Meter
Thank you Bob. I am fortunate in that my 130, unlike about all my other Tek gear, is very clean. Possibly came out of a clean room, who knows. No evidence of tobacco tar or even much dust.
toggle quoted message
Show quoted text
Will also download the reworked manual. My manual is copyright 1960, and is rather bare bones. It is an original Tek, but the circuit description section is about a third of the size of the one in a later manual that I printed out last night. Got the link for that manual at W140.com. The manual I have is rather odd in that some of the print is blue. Only Tek manual I have that is like that. On 2/17/22 20:13, Bob Albert via groups.io wrote:
On my 130, the variable oscillator won't oscillate. |
|
Re: A sick 465B
After replacing the CRT with an apparently new part (the anode lead was unbent and had no soot on it, and was strapped to the neck with a latched rubber belt) I now have absolutely no traces on the CRT. I replaced R4124 (which had drifted high by 25%) with a 22M metal film resistor, but still no traces, so I started taking measurements:
* the heater on the new CRT measures 13¦¸, which is the same as the old CRT (which produced a trace, even if it was distorted). * the Z-axis test point responds to the INTENSITY control, ranging from 14 V to 88 V. * the HV test point reads only -1220 V, which is about half what it should read. I double checked the HV probe and meter using the +55 V and +110 V rail test points, and they read close enough to assure me that the meter and HV probe were measuring correctly (~60 V and ~120 V, respectively). So it looks like I have something wrong in the HV section. I¡¯ve had something similar happen on a 475 (or was it a 475A) that was working on, and was not able to get the grid bias adjusted. It turned out to be something wrong with the precision thick-film resistor that feeds the cathode voltage back to the regulator circuitry. I¡¯m chasing that down now. I¡¯m just trying to get to a point where I can verify that the new CRT isn¡¯t faulty too, but the scope is not cooperating. ¡ª Jeff Dutky |
|
Re: Type 130 L-C Meter
Bob Albert
On my 130, the variable oscillator won't oscillate.
On Thursday, February 17, 2022, 05:08:34 PM PST, Tom Lee <tomlee@...> wrote: Hi Dave, The docs at VintageTek are great. The gentleman who wrote the three-part article did a remarkable job of documenting his restoration of his 130. He even restored the manual (he did more than photoshop an existing manual -- he rewrote it!). After you've read his docs, you'll understand how that unit works at a deep level. If the signal that drives the Schmitt looks good (both amplitude- and dc-wise), the number of possible faults goes way down. A few component checks/substitutions should get your unit functioning again. Then perform a cal, and it should be as good as new. Good luck hunting! --Cheers Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 350 Jane Stanford Way Stanford University Stanford, CA 94305-4070 On 2/17/2022 16:54, Jerome D Leach wrote: Thank you Tom, will take a closer look at the resistors in that |
|
Re: Type 130 L-C Meter
Dave, Stephen and Albert,
toggle quoted message
Show quoted text
My unit is serial 90XX (forgot already), and as was noted, has a 6DJ8 for V70, although the chassis panel lists the 6BQ7 as well. Not sure if I am going to the dungeon tonight, pretty beat after work today, but will take the pointers thus so graciously given and look at it tomorrow. When I prodded it with the 'scope probe, didn't get the voltages, so will check those along with the frequency and report back. Been given a lot of information and after a good nights rest, will put fresher eyeballs on it. As for the calibration, I am fortunate to have snagged an S-30 Delta standard somewhere a few years ago. Have only given it a cursory inspection, but it appears to have never been tampered with. In fact, it looks almost new. On 2/17/22 14:45, Dave Wise wrote:
No big deal, I just wanted to ensure the archive doesn¡¯t mislead the next guy. |
|
Re: Tek TDS-3000 V3.41 Firmware
To follow up on my previous message, I just noticed that when I copied the V3.41 files from my computer to a memory stick, for carrying to my old laptop in the shop, each file was swelled by 20 to 30 kB. This might have been just enough to put the third group of files beyond the capacity of the disk.
Tomorrow I'll try downloading them directly to the old laptop with a 3-1/2-inch drive. Bruce, KG6OJI |
|
Re: Type 130 L-C Meter
Hi Dave,
toggle quoted message
Show quoted text
The docs at VintageTek are great. The gentleman who wrote the three-part article did a remarkable job of documenting his restoration of his 130. He even restored the manual (he did more than photoshop an existing manual -- he rewrote it!). After you've read his docs, you'll understand how that unit works at a deep level. If the signal that drives the Schmitt looks good (both amplitude- and dc-wise), the number of possible faults goes way down. A few component checks/substitutions should get your unit functioning again. Then perform a cal, and it should be as good as new. Good luck hunting! --Cheers Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 350 Jane Stanford Way Stanford University Stanford, CA 94305-4070 On 2/17/2022 16:54, Jerome D Leach wrote:
Thank you Tom, will take a closer look at the resistors in that circuit, and will then report back. |
|
Re: Type 130 L-C Meter
Jean-Paul,
toggle quoted message
Show quoted text
Given my state of electronics expertise, ALL notes help, and I read them closely. Thank you. Dave On 2/17/22 05:27, Jean-Paul wrote:
bonjour ¨¤ tous |
|
Re: Type 130 L-C Meter
Kerry and Tom, thank you both for the link to the Tek Museum's video on the 130, will try to watch it tonight. Have poked around the Museum's website, but haven't availed my self of all the resources.
toggle quoted message
Show quoted text
Dave On 2/17/22 03:47, Tom Lee wrote:
VintageTek received permission to post the three-part article. See |
|
Re: Type 130 L-C Meter
Thank you Tom, will take a closer look at the resistors in that circuit, and will then report back.
toggle quoted message
Show quoted text
Dave (yeah, go by Dave, never much cared for Jerome) On 2/16/22 23:21, Tom Lee wrote:
Hi Jerome, |
|
Tek 2715 75 to 50 ohms conversion
Hi,
I want to change my Tek 2715 75 ohms input to 50 ohms. From what I read in the service manual, its just the input connector that has a 25 ohms resistor, internals of the 2715 is all 50 ohms. Has anyone done this modification? Do I to buy a new conector or its a question of moding the installed conector? Any help is greatly apreciated. Alfredo |
|
Tek TDS-3000 V3.41 Firmware
In preparing to update the firmware on my TDS3052 scope to V3.41, I downloaded the file from the Tektronix website and began transferring it to four 3-1/2-inch disks as instructed. The first two disks wrote fine, but with the the third I began getting a message "insufficient space on disk." After trying several discs and getting the same result, I checked the file lengths. To my surprise they were:
#1 - 532kB on disk for 3 items #2 - 397kB on disk for 4 items #3 - 1.5 MB on disk for 3 items #4 - 815kB on disc for 3 items Something seemed incorrect so I downloaded the file again, but with the same results. Have others experienced this? Bruce, KG6OJI |
Raymond Domp Frank
ebrucehunter
to navigate to use esc to dismiss