OT: AT5005 spectrum analyzer display


Ed Breya
 

I picked up this 500 MHz SA for cheap, because the CRT display is very dim, although it appears to work otherwise. I was hoping that some internal adjustments would fix it right up, but no. The unit is labelled Atten Instruments, model AT5005, and appears to be a Chines knockoff of the Hameg HM5005 - or maybe they're all made in China anyway. I couldn't find a manual for it, but did find the one for Hameg 5010, which includes schematics and more. It looks like the basic units are the same, especially the PS and CRT circuits, so I have what I need to check it out eventually. This is low priority, but it could be a handy toy SA for limited field use and such - it's definitely more portable than the good old real SAs I'm used to.

Just wondering if anyone happens to be familiar with this unit and common problems with it, to maybe find a quick fix. I haven't made any of the usual internal checks yet. One thing I noticed is that the focus adjustment needs to be at one extreme for a sharp, but barely visible display. I'm guessing there's something wrong in the CRT HV circuits, rather than the CRT having gone bad - unless that's one of the common problems with these.

Ed


 

Can you see the CRT part number ?

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Ed Breya via Groups.Io <edbreya=yahoo.com@groups.io> 於 2018年6月11日 上午12:58 寫道:

I picked up this 500 MHz SA for cheap, because the CRT display is very dim, although it appears to work otherwise. I was hoping that some internal adjustments would fix it right up, but no. The unit is labelled Atten Instruments, model AT5005, and appears to be a Chines knockoff of the Hameg HM5005 - or maybe they're all made in China anyway. I couldn't find a manual for it, but did find the one for Hameg 5010, which includes schematics and more. It looks like the basic units are the same, especially the PS and CRT circuits, so I have what I need to check it out eventually. This is low priority, but it could be a handy toy SA for limited field use and such - it's definitely more portable than the good old real SAs I'm used to.

Just wondering if anyone happens to be familiar with this unit and common problems with it, to maybe find a quick fix. I haven't made any of the usual internal checks yet. One thing I noticed is that the focus adjustment needs to be at one extreme for a sharp, but barely visible display. I'm guessing there's something wrong in the CRT HV circuits, rather than the CRT having gone bad - unless that's one of the common problems with these.

Ed



 

Attached operation manual , there are block diagram only , I do not have the service manual , hope it help .
Rd Tony

From: Yiu On Tony C via Groups.Io <tonycheung_hk=yahoo.com@groups.io>
To: TekScopes@groups.io
Sent: Monday, June 11, 2018 7:42 AM
Subject: Re: [TekScopes] OT: AT5005 spectrum analyzer display

Can you see the CRT part number ?

從我的 iPhone 傳送

Ed Breya via Groups.Io <edbreya=yahoo.com@groups.io> 於 2018年6月11日 上午12:58 寫道:

I picked up this 500 MHz SA for cheap, because the CRT display is very dim, although it appears to work otherwise. I was hoping that some internal adjustments would fix it right up, but no. The unit is labelled Atten Instruments, model AT5005, and appears to be a Chines knockoff of the Hameg HM5005 - or maybe they're all made in China anyway. I couldn't find a manual for it, but did find the one for Hameg 5010, which includes schematics and more. It looks like the basic units are the same, especially the PS and CRT circuits, so I have what I need to check it out eventually. This is low priority, but it could be a handy toy SA for limited field use and such - it's definitely more portable than the good old real SAs I'm used to.

Just wondering if anyone happens to be familiar with this unit and common problems with it, to maybe find a quick fix. I haven't made any of the usual internal checks yet. One thing I noticed is that the focus adjustment needs to be at one extreme for a sharp, but barely visible display. I'm guessing there's something wrong in the CRT HV circuits, rather than the CRT having gone bad - unless that's one of the common problems with these.

Ed



Ed Breya
 

Thanks Tony. Also, regarding your question about the CRT ID, I had the unit opened up for a while to try tweaking the settings and see the basic layout, and look for any obvious faults - none found. But, I put it back together already. Next time I open it I will look at the CRT closely. It's possible it's indicated in the HM5010 service manual. I don't recall that it had a parts list, but some of the part types are shown on the schematics - maybe the CRT too.

Ed


Ed Breya
 

The HM5010 manual schematics shows the CRT is D14-364, which googles out to be very common, and Hameg uses it in some of there other products.

Ed


 

You have the one on hand are Chinese type CRT , may not direct replacement .
Tony

From: Ed Breya via Groups.Io <edbreya=yahoo.com@groups.io>
To: TekScopes@groups.io
Sent: Monday, June 11, 2018 10:56 AM
Subject: Re: [TekScopes] OT: AT5005 spectrum analyzer display

The HM5010 manual schematics shows the CRT is D14-364, which googles out to be very common, and Hameg uses it in some of there other products.

Ed


Ed Breya
 

I fooled around with this a little more today. The CRT HV stuff seems to be about right, and I bypassed the video (blanking) amplifier, with no change in intensity. Instead of getting buried in details, I decided to take a drastic measure and just jumpered the G1-K on the CRT - this would allow maximum (or excessive) beam current and the brightest trace possible. Still no effect, so it looks like this one is a goner, but will be an ideal candidate for CRT rejuvenation experiments. Next time I'm inclined to fool around with the rejuvenator, I'll give it a shot and see what happens, but for now I'll set it aside. I probably have a socket that will fit, and just need to get the heater voltage spec for this tube, and some time.

Ed


r221b@juno.com
 

Hello Ed, I used to have a Hameg 5005 which should be the same as your AT 5005. I have the service and operating manuals including schematics and alignment instructions. I'll be happy to send them to you if you send me your email address.

Rich F. r221b@juno.com


 

Upload it to the files section?

Regards

----- Original Message -----
From: <r221b@juno.com>
To: <TekScopes@groups.io>
Sent: Wednesday, June 13, 2018 11:39 PM
Subject: Re: [TekScopes] OT: AT5005 spectrum analyzer display


Hello Ed, I used to have a Hameg 5005 which should be the same as your AT 5005. I have the service and operating manuals including schematics and alignment instructions. I'll be happy to send them to you if you send me your email address.

Rich F. r221b@juno.com


Ed Breya
 

Thanks Rich, I'd appreciate that info.

Unfortunately, this one's a goner. I decided to do a "quick" CRT check and rejuvenation attempt, since I found a correct socket on-hand. I wired it up and hit it with a B&K 470. It was unresponsive - so much so that I thought the 470 wasn't working right, which led to a wild goose chase of checking and rechecking the 470 and the wiring, but all seemed normal. The CRT had virtually no K emission at all, and was even dimmer yet when put back in-circuit, so the process did not help, but definitely did something to it. The CRT was too far gone, or too skimpy on K coating anyway. This is the first CRT I've tried that didn't show at least some improvement.

I'll be saving some of the RF sections and parts for possible re-use, so it's good to have schematics, etc for reference. I've already popped the CRT vacuum and put it in the e-waste box for the next recycling run, and the carcass will be stripped soon. Oh well, good thing it was only ten bucks, so no big loss. I got another rejuvenation data point, and some parts out of the deal.

Ed


Jokken Feldhaar
 

Hi Ed,

I am one of the developers of the HM 5005, and also the HM 5010.

The focus problem may be linked to resistors in the 2000 Volt feedback path that have altered their value - they were at their voltage limit when operated, and were not long time stable.

For further questions or information - just contact me ;-)

Regards, Jochen DH6FAZ


Am 10.06.2018 um 18:58 schrieb Ed Breya via Groups.Io:

I picked up this 500 MHz SA for cheap, because the CRT display is very dim, although it appears to work otherwise. I was hoping that some internal adjustments would fix it right up, but no. The unit is labelled Atten Instruments, model AT5005, and appears to be a Chines knockoff of the Hameg HM5005 - or maybe they're all made in China anyway. I couldn't find a manual for it, but did find the one for Hameg 5010, which includes schematics and more. It looks like the basic units are the same, especially the PS and CRT circuits, so I have what I need to check it out eventually. This is low priority, but it could be a handy toy SA for limited field use and such - it's definitely more portable than the good old real SAs I'm used to.

Just wondering if anyone happens to be familiar with this unit and common problems with it, to maybe find a quick fix. I haven't made any of the usual internal checks yet. One thing I noticed is that the focus adjustment needs to be at one extreme for a sharp, but barely visible display. I'm guessing there's something wrong in the CRT HV circuits, rather than the CRT having gone bad - unless that's one of the common problems with these.

Ed



Ed Breya
 

Hi Jochen,

Thanks for the info. Unfortunately, the CRT was no good anyway. I pretty much proved it by running it wide open, with G1-K shorted. I had measured the 2 kV (not very accurately, maybe +/-10%) and found it about right during my attempts to attain useful brightness. The HV FB string could have had problems too, but the regulator loop was working, evidenced by the loop opamp having the right conditions. So, the HV could have been off a little, but close enough that I should have (with G1-K short) gotten a strong beam - or overloaded the HV. Neither happened, just a barely visible, but otherwise correct trace - just like before. My attempts at rejuvenating the CRT also indicated virtually no K emission, with no improvement (actually, got worse) after zapping it a number of times.

Ed