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MR501 HT Success!

 

Well, 5 resistors and a rotary switch did the trick, I now have a variable range "huntron tracker" up and running in that modded MR501.

it is currently in "ugly" prototype stage, literally held together with some tape, and running on an extender cable but I wanted to be sure before cutting the panel that the idea was workable with no surprises. I still have to tweak some gains to prevent traces falling off the screen, but I have great performance from low voltage to about 10Vfs, and easily within the range of all the controls.

I can send some pics to anybody interested, the process was very simple:

1. attach twisted pair to rear 25VAC wining on 13A/B, run that to a small pcb with the range resistors.
2. remove rear connector X/Y connections on 16/17 for re-use.
3. remove the vertical gain pot from the front.
4. install 3 pos rotary (min. grayhill) in its place, run to pcb to select input voltage from divider pcb..
5. add vertical current sense 1K resistor across the vertical input.
6. connect common and horiz input to the pcb.
7. cable BNC for sample input.

now I have to add a BNC to front, thankfully the shell goes to ground/circuit common, or an insulated BNC would be needed. using a BNC to mini-grabber cable makes testing a snap.

there is a bit of end trace distortion (most visible on circular cap traces) due to other rectifiers sharing the same core transformer as the test winding. very minor issue, but interesting to see how loads affect the primary transformer reflected back to the line.

I looks very usable, certainly more so than the raw MR501 I started with.I will provide better pics and info once it's finished.
all the best,
walter (walter2 -at- sphere.bc.ca
sphere research corp.

Glydeck
 

Walter,

Would love to see pictures. Could they be posted to groups.io?

George kd6new

On Jul 20, 2019, at 6:54 PM, walter shawlee <@walter2> wrote:

Well, 5 resistors and a rotary switch did the trick, I now have a variable range "huntron tracker" up and running in that modded MR501.

it is currently in "ugly" prototype stage, literally held together with some tape, and running on an extender cable but I wanted to be sure before cutting the panel that the idea was workable with no surprises. I still have to tweak some gains to prevent traces falling off the screen, but I have great performance from low voltage to about 10Vfs, and easily within the range of all the controls.

I can send some pics to anybody interested, the process was very simple:

1. attach twisted pair to rear 25VAC wining on 13A/B, run that to a small pcb with the range resistors.
2. remove rear connector X/Y connections on 16/17 for re-use.
3. remove the vertical gain pot from the front.
4. install 3 pos rotary (min. grayhill) in its place, run to pcb to select input voltage from divider pcb..
5. add vertical current sense 1K resistor across the vertical input.
6. connect common and horiz input to the pcb.
7. cable BNC for sample input.

now I have to add a BNC to front, thankfully the shell goes to ground/circuit common, or an insulated BNC would be needed. using a BNC to mini-grabber cable makes testing a snap.

there is a bit of end trace distortion (most visible on circular cap traces) due to other rectifiers sharing the same core transformer as the test winding. very minor issue, but interesting to see how loads affect the primary transformer reflected back to the line.

I looks very usable, certainly more so than the raw MR501 I started with.I will provide better pics and info once it's finished.
all the best,
walter (walter2 -at- sphere.bc.ca
sphere research corp.




nonIonizing EMF
 

On Sat, Jul 20, 2019 at 03:54 PM, walter shawlee wrote:


I can send some pics to anybody interested
Seems like a copy and paste of this post thread with the photos (sent here or uploaded directly to Tekwiki) can help someone in the future and show off your project on the Tekwiki site for posterity. Seems to be a pertinent Tektronix piece of equipment that can be documented for the history, and reference, records.

I'm interested in looking at the images and can upload to the Tekwiki site if you need as I did with the PMI/Wavetek 1038 and EDX-1 systems.

For the Tekwiki... we'll have to determine what to call the equipment first and foremost, e.g. "Sphere Research Corp. MR501 huntron tracker" or "Shawlee MR501" :-|)

Thoughts, suggestions?

Lawrance A. Schneider
 

Where is tekwiki?


Much to my surprise, no one has claimed the 2445B cover. I saw someone trying to commit highway robbery on ebay asking $100 for a cover. I just can’t do that. Since I still have it, I’ll ask $20 plus shipping. I hope someone lay claim to it.


Thank you, larry

On Jul 21, 2019, at 7:15 PM, nonIonizing EMF <nonionizingemf@...> wrote:

On Sat, Jul 20, 2019 at 03:54 PM, walter shawlee wrote:


I can send some pics to anybody interested
Seems like a copy and paste of this post thread with the photos (sent here or uploaded directly to Tekwiki) can help someone in the future and show off your project on the Tekwiki site for posterity. Seems to be a pertinent Tektronix piece of equipment that can be documented for the history, and reference, records.

I'm interested in looking at the images and can upload to the Tekwiki site if you need as I did with the PMI/Wavetek 1038 and EDX-1 systems.

For the Tekwiki... we'll have to determine what to call the equipment first and foremost, e.g. "Sphere Research Corp. MR501 huntron tracker" or "Shawlee MR501" :-|)

Thoughts, suggestions?


nonIonizing EMF
 

On Sun, Jul 21, 2019 at 04:51 PM, Lawrance A. Schneider wrote:


Where is tekwiki?
Here is Tekwiki: http://w140.com/tekwiki/

I'm thinking can be considered a Third Party Product: http://w140.com/tekwiki/wiki/Category:Third-party_products

momemeca
 

Hello Lawrance, Would you know if this cover would fit a 2465B?If so, I would love to buy it from you.Cheers, Rick.P.S. I am from Australia 😊Sent from my Samsung Galaxy smartphone.

-------- Original message --------From: "Lawrance A. Schneider" <llaassllaaass@...> Date: 22/7/19 09:51 (GMT+10:00) To: TekScopes@groups.io Subject: Re: [TekScopes] MR501 HT Success! Where is tekwiki?Much to my surprise, no one has claimed the 2445B cover.  I saw someone trying to commit highway robbery on ebay asking $100 for a cover.  I just can’t do that.  Since I still have it, I’ll ask $20 plus shipping.  I hope someone lay claim to it. Thank you, larry> On Jul 21, 2019, at 7:15 PM, nonIonizing EMF <nonionizingemf@...> wrote:> > On Sat, Jul 20, 2019 at 03:54 PM, walter shawlee wrote:> >> >> I can send some pics to anybody interested>> > > Seems like a copy and paste of this post thread with the photos (sent here or uploaded directly to Tekwiki) can help someone in the future and show off your project on the Tekwiki site for posterity.  Seems to be a pertinent Tektronix piece of equipment that can be documented for the history, and reference, records. > > I'm interested in looking at the images and can upload to the Tekwiki site if you need as I did with the PMI/Wavetek 1038 and EDX-1 systems. > > For the Tekwiki... we'll have to determine what to call the equipment first and foremost, e.g. "Sphere Research Corp. MR501 huntron tracker"  or "Shawlee MR501" :-|)> > Thoughts, suggestions?> > >