Agilent 53220A assistance

[mskobier]

Hi All,
Been quite a while since I was here last. Today, while wandering around the local scrap metal salvage yard I stumbled upon an Agilent 53220A frequency counter laying in the mud. Made me sad to see it that way, so it and a few other goodies followed me home. 

So I get the 53220A home and cleaned up. It has definitely seen better days. However, there is no obvious damage other than a few scratches and gouges on the plastic around the front.

Since it had been out in the rain, I disassembled it and dried everything out, then put it back together. Plugged it in, and the power supply fan spun up, and after a short period of time, a number of green lights started flashing in the main board. However, there was not display of any sort on the display screen.

So I found an owners manual and service guide on line. Checked all the voltages on the main board, all were good. Checked the voltage on the front panel, and found all of the reference voltages good. There are three test points that do not have voltages printed beside them. Tow of the three were 3.3v, and the third one did not have any measurable voltage.

So with that information, I downloaded and installed bench view. Hooked up a usb cable, and ran bench view. Benchview found the 53220A, and connected. I connected a 10mhz signal to the inputs, and I got a matching frequency in Benchview. This worked for both channels. Every time I changed a setting in bench view, I would hear a click in the counter. So it appears the unit is actually working.

I next hooked it up via a LAN cable, made a couple of adjustments to the laptop, and was able to connect. No problems there. However, a pass word was set, and without the display, I have not yet figured out how to reset the password. The manual tells you how, but without the display I have not been successful.

So with all of that said, It looks like it needs a replacement PCA Front Panel board, or possibly just a display (not likely). I have sent an email to Keysight, but I am afraid they are going to want way too much for a replacement board. I'm only into this thing <$5.00, so I do not want to spend several hundred on it (a couple of hundred maybe), as it won't be used all that often, and I already have three working counters. But it would be nice to have something on the bench as modern as the 53220A.

I also need directions (button sequence to be pushed) on how to reset the LAN password.

Sorry for the long post. Figured it better to post what I have already done so you guys know status.

Mitch

[PTR_1275]

What section is the password reset meant to be in when doing it from the front panel? I’ve got a 53220a and can list the button presses for you, but I can’t seem to find a reset section.

Is the keypad working? Do the LED’s change from 1 to 2 when changing channels?

[PTR_1275]

Just looked at the manual and to reset the password you need to do a lan reset

From home screen
Utility
Softkey 2
Softkey 3
Softkey 5
Wait 30 seconds or so

Mine has then defaulted to
Lan on
DHCP

If you want button presses to set it up for a manual ip config, let me know and I’ll work that out.

[PTR_1275]

Oh, and nice score for $5. It is sad to see bits of equipment left out in crappy conditions. People just see it as a box. If it’s been sent for scrap, it’s not worth anything g really, so they treat it as it is worthless

[nfmax]

Check the programming manual - does this counter have a DISPLAY OFF command? If the instrument is set to power up in last state, this might be all that's wrong.

[mskobier]

Thanks for the replies all. Yes, it really is a shame some of the things I have seen in the salvage yard.
Yes, it was a good score. But that's only part of what I found. A Bird Thruline watt meter that wasn't too banged up. It cleaned up nicely. I already have two, so this one will be tested then passed on to a new home. And finally a KIKUSUI COS 1611 X-Y Display that works fine. Just had to clean the mud off. I've always wanted to build an oscilloscope clock, and this display will work perfect for that. The total sum for the trip was $10.00.

Thanks for the push button sequence for resetting the password. I'll try that here in a bit to make sure it cleared the password.

Yes the unit has the ability to turn off the display. But according to the manual, it should turn back on whenever a key is pressed. Using the manual as a guide, I also worked through the button sequence to turn the display from dim to bright. No change. I also removed the battery when I took it apart. I would think that it would clear the temporary settings.

The keypads all seem to work, as in they beep when I press them. None of them except the power on indicator and the Data Log button light up when they are pushed. There are no indicator lights on the channel buttons. Something else, the little green leds on the main circuit board change which ones are lit and flashing or on solid depending on which buttons are pushed. There are two sets of these leds. The set in the front right corner pretty much stays on continuous, but does blink when buttons are pushed, the second set in the middle of the main board change when some of the buttons are pushed.

Again, thanks for all the assistance.

[PTR_1275]

Mine definitely has LED’s behind the 1 & 2 for channel selection. I’ll have a look in the morning about the other LED’s, i know there’s some really bright ones inside, but never paid enough attention to them. Can you see both sets of them easily with the case on? If you can list what buttons you pressed that changed the internal LED’s I can test that on my unit.

Another thought, have you looked at the display with a bright torch? It could be the backlight that’s died, making the display almost impossible to see without some assistance. I feel keysight will quote some stupid amount, or say the part isn’t user serviceable and then quote you for them to do the repair for a even higher amount.

[mskobier]

OK, messing with the unit again this morning, I discovered that there are actually lights behind the channel buttons. They are not very bright, but they are definitely lit up.

PTR_1275, beside the two channel indicators and the data log button (when pressed), do you have any other buttons with lights behind them? If not, then maybe the board is ok, and just the display is toast.

I also took a bright flashlight an tried to light up the display. No luck. From what I could see, it looks like the display may have gotten water in it. Kind of splotchy looking inside with the flash light.

I'm leaning towards trying to locate a replacement display instead of the board.

Is it possible that the firmware somehow got corrupted? would things be working like they are? Since updated firmware is available, would it be worth the effort trying that to see if it corrected the display issue? These are just some questions I have been asking myself. I really do not think it would be working t all if the firmware was corrupt. I also do not know if I can flash new firmware without a display.

More to come I'm sure.

[mskobier]

I spent a bit more time working with the unit. At this point, without a schematic I'm left with probably buying a replacing board at around $500.00. I don't think I am going to do that.
 I did notice a couple of interesting things when I had it apart. I was able to get the display module manufacturer number off the back of the display module. They are available from China, through a number of distributors. But I do not think that is the main problem.

When I had it apart, I did note that there a pair of LEDs behind most of the buttons. Only three of the buttons light up when they are pushed. The two channel LEDs, and they are pretty dim. when the Data Logger button is pushed, that LED backlight is fairly bright. So I am thinking it is possibly a power issue to the display module and the LEDs.

I wrote down the various chips on the UTG PCA Front Panel board. Specifically the display driver IC. Time to do a little research on the display module and see if I can figure out which pin powers the display. Then a voltage check there should provide some useful info.

For those of you that know way more than I do, does this seem like a valid plan to troubleshoot the display?

Any and all info, experience, and constructive opinions will be greatly appreciated.

[PTR_1275]

The channel LED’s on mine are quite dull compared to the data log button too. “1” is definitely duller than “2”

I think you’re on the right path, but I don’t have much experience in debugging things this complex.

[TheSteve]

The flat flex cable that connects the LCD module is very picky on these units. Although being it was sent for scrap you'd think it had a problem even before it got wet.
I'd say there is no chance it is a firmware related problem.