DANA 5524 – This beautiful state-of-the-art-of-its-time voltmeter is the most remarkable equipment I have until now. It is solid-state, but everything is done with discrete transistors (some of them are one-case matched pair), none IC’s. Six pretty 30mm nixies digital multimeter with auto range function and an amazing military grade assembling, in a clean and neat construction shown on the pictures. I bought it in march of 2006 at eBay for a bargain price: USD12.00 !!!  But its heavyweight (25kg) and dimensions made the freight expensive for me (at flat rate surface via USPS – cheapest possible): USD100.00, and the customs taxes added more USD120.00 to the bill. The seller was very friendly and he gave me support during the long time I had to wait. He had two units. I don’t know if the other one was sold… Actually the unit I own belonged to U.S. Air Force, bar code A485710.

Before it arrived, I have bought, also in eBay, its original USER/SERVICE manual, USD18.00 plus USD19.00 freight, it is a very detailed sheet and also have some functions description and theory of operation, so I started reading the manual prior to have the equip in my hands. I was very impressed with their specifications; obviously it was a top of its kind, at least for that time (I wonder if it don’t stand at the top until today...).

When the 5524 finally arrived (3 months later), I already knew how to turn on and test their basic functions. I took off the fuse of the heating element, because it operates at 400Wh, and since I live in a hot place I think I will not need it. Without the heating element the unit consumption stills 90Wh!!! I kept the fan operating, because I like its noise – I think I’m on a submarine or something like that…

The display showed random numbers no matter what function was selected, and the numbers, after power on, started to count down. So I opened the cabinet, removing the eight screws on the front panel and pulling off the chassis with the help of the side holders.

 

Important: if your 5524 is not hardly tied to the 19” rack or something really strong,

when you pull the unit off the cabinet, it can fall over your feet, with the weight of the panel,

the chassis, and the other parts (that slides towards you), because the die casting cover case

are extremely lightweight if compared to the inner chassis.

(fix it on the rack by four “truck wheel screws”)

 

The ball bearings of the side brackets make the opening extremely soft, as if it should be opened all the time. Once totally opened, the slide brackets locks, and you need to unlock them to close the chassis again.

Inside the chassis there is a space for a desiccant, which is missing in my 5524, but the cover says to replace it every time the chassis is opened, I put a few silica gel bags inside it and I think it will be all right.

Well, as the counting were perfect – even being downwards – I presumed that the decade boards were ok, and the range control, also, because the dot moved correctly from left to the right after the counting go to “1.000” to “999.9”, for example, and so on. If I was right, I had 50% less boards to search the problem – only the function boards. After several visual inspections on the function boards, I found only the reference and buffer amp board that had some resistors with alterations in their appearance and I decided to replace them (see page 6-37 of the manual). All discrete transistors of that region of the circuit were tested, but all them were OK. I replaced: R39 – 220ohm, R42, R44, R46 – 15ohm, R45 – 3k9ohm, R43 – 22ohm. I took care in select the best values between the good 1W low noise metal-film types I had from PHOENIX. Well, easy to say that it was just a countermeasure, because all of the removed parts had correct measured values, despite of their rugged appearance. And after all that, no changes in the symptom of the unit were noticed.

So I started to disassembly the unit to see if there was a disconnected wire or something like that. The first screws that I took off were from the cover of the switching board, in the very front of the chassis, at the right corner, and I saw no relays on that board!!! I almost had a heart attack!!! “These relays must be impossible to find”, I thought. But happily they were glued on the cover, by a kind of foam that must be degraded with the time, didn’t saw them when I took off the cover. And there they were, all them!!!

After connecting each relay on its place, and turning on the unit, the 5524 resurrected. All this happened in a 2-week interval, because the 5524 were on my work, not at my home, and I had only my lunchtime to try to fix it (one hour per day, including the time to swallow the food). I decided to keep the multimeter at there because I have not high accurate voltmeters at my home, such as the brand new Agilent 34401 we use where I work (believe me, the 5524 was my first digital multimeter!!!). The 34401 is certified to be calibrated until the end of 2008, good!

I connected the two units, the 5524 and the 34401 on AC, and DC regulated power supplies, the difference between them was on the 6th digit!!! Ohms measurement also (but it is 4-wire, only) AMAZING!!! I felt truly happy because now I have a high grade and accurate equipment. I could not see any major difference in AC response until 400kHz sinusoidal, and 150kHz square wave!!!!

The fixing of this unit is surprisingly pleasant, and made easy with the fine job the people of DANA LABs did on it. I think that the guys who designed it thought that it would be used in a war, where reliability and time is essential. So you can dismantle the entire unit in a half of hour, if you need. Maybe the precision of 5524 was required to calibrate altimeters, tachometers, pressure and temperature sensors, and other airplane and related instruments, in whose the life of a lot of people depends, on war situations.

I also made some extension brackets, with fiberglass and gold plated connectors. The gerber drawing of the board is here. In case you need to calibrate your unit, is better to have a sort of them. Luckily, I didn’t need to touch on the calibrated points of my 5524. It is specified to be used from 50Hz to 400Hz mains supply frequency, and 105-125VAC. You can see the label here.

 

 

Beautiful rig !!!! I had to use my wife's kitchen and mobilia to take these pictures, because there were no room enough to do it at the shack.....

 

 

 

Bar Code and Identification Label....

 

 

The rear plugs and lots of patents registered for DANA Labs....

 

 

Amazing construction..... to support severe environments conditions....

 

   

 

Press the lock mechanism on both sides to close the drawer again.

At the left end of the image are the heating elements.... 400W of heat !!!!

 

                                   

 

Left side: Material to build extension brackets: proper connector and straight-connected PCB.

Right side: Built extension bracket. Mine used a 44 pin type, made by Clip-Tech (Brazilian brand). I

had to cut out some pins to make it fit on the 36 pin board used. The part number of the connector I used  is O4-O153-C44

 

 

Equipment running with the extension bracket.....just for pictures....

 

 

Here you can see the ball bearings that make the drawer slides smoothly....

 

 

Silica gel bags inside this cover....

 

 

ELECTRICAL SPECIFICATIONS (as per stated on page 1-6 of the manual):

 

The only mistake I could remark is that in my unit I measured 90W of power consumption, and the specs says only 50W ( I took off the heather fuse). In page 2-3 of the same manual you found that the heater operate with 400W. It has an thermostat, but is too much W/h to be spent on a hobby/home test set.

 

DC VOLTAGE MEASUREMENTS    
Full scale ranges:   ±10.9999, ±109.999, ±1099.99 V (Max 1000V)
Accuracy: Short term, 24 hours, 23±1ºC ±0.005% of reading ±0.001% of full scale
  Long term stability, 6 months ±0.001% per month
  Temperature coefficient ±0.0005% of reading ±0.0002% of full scale per ºC
Response time: Digitizing 15 milliseconds
  Digitizing with polarity change 25 milliseconds
  Range change 250 milliseconds per range
Full scale step function settling time (to 0.1%): 500 milliseconds with up to 100k-Ohm source
Commom mode rejection: DC 140dB with up to 100 Ohm in either lead
  AC, 61Hz and below 120dB with up to 100Ohm in either lead
Normal mode noise rejection:   60dB min, 50Hz and up; increasing 18dB/octave;
    80dB min, 300Hz and above
Input resistance - at or off null: 10 range 10,000 Megohms ------------> (WOW!!!!!)
  Other ranges 10 Megohms

 

DC RATIO VOLTAGE MEASUREMENTS  
Full scale ranges:   ±1.09999:1, ±10.9999:1, ±109.999:1
Accuracy: Short term, 24 hours, 23±1ºC ±0.004% of reading ±0.001% of full scale
  Long term stability, 6 months ±0.0003% per month
  Temperature coefficient ±0.0005% of reading 0.0002% of full scale per ºC
Response time: Digitizing 15 milliseconds
  Digitizing with polarity change 25 milliseconds
  Range change 250 milliseconds per range
Full scale step function settling time (to 0.1%): 500 milliseconds with up to 100k-Ohm source
Commom mode rejection: DC 140dB with up to 100 Ohm in either lead
  AC, 61Hz and below 120dB with up to 100Ohm in either lead
Normal mode noise rejection:   Same as absolute (input only)
Input resistance - at or off null: 10 range Signal, 10,000 Megohms; ref, 20 Megohms
  Other ranges Signal, 10 Megohms; ref, 20 Megohms

 

DC VOLTAGE MEASUREMENTS, FAST  
Full scale ranges:   ±10.9999, ±109.999, ±1099.99 V (Max 1000V)
Accuracy: Short term, 24 hours, 23±1ºC ±0.0005% of reading ±0.001% of full scale
  Long term stability, 6 months ±0.001% per month
  Temperature coefficient ±0.0005% of reading 0.0002% of full scale per ºC
Response time: Digitizing 15 milliseconds
  Digitizing with polarity change 25 milliseconds
  Range change 250 milliseconds per range
Full scale step function settling time (to 0.1%): 500 milliseconds with up to 100k-Ohm source
Commom mode rejection: DC 140dB with up to 100 Ohm in either lead
  AC, 61Hz and below 94dB with up to 100Ohm in either lead
Normal mode noise rejection:   60dB min, 50Hz and up; increasing 18dB/octave;
Input resistance - at or off null: 10 range 10,000 Megohms ------------> (WOW!!!!!)
  Other ranges 10 Megohms

 

MILLIVOLT MEASUREMENTS    
Full scale ranges:   ±109.999, ±1099.99 millivolts
Accuracy, 3 months: 100mV range ±0.01% of reading ±0.02% of full scale
  1000mV range ±0.01% of reading ±0.005% of full scale
  Temperature coefficient ±0.001% of reading 2 microvolts per ºC
Response time (to 0.01%): Step response 1 second
  Range change 250 milliseconds per range
Full scale step function settling time (to 0.1%) 500 milliseconds with up to 100k-Ohm source
Commom mode rejection: DC 140dB with up to 100 Ohm in either lead
  AC, 61Hz and below 120dB with up to 100Ohm in either lead
Input resistance: 10 range 100 Megohms minimum
     
AC MEASUREMENTS    
Maximum voltage rating:   500Vrms, 50Hz to 10kHz, decreasing to 150V at 50kHz and above
Full scale ranges:   ±10.9999, ±109.999, ±1099.99 V (Max 1000V)
Accuracy, 3 months: 50Hz to 10kHz: ±0.09% of reading ±0.01 full scale
  10kHz to 50kHz: ±0.2% of reading ±0.05 full scale
  50kHz to 100kHz: ±0.9% of reading ±0.1 full scale
  Temperature coefficient ±0.01% of reading and ±0.0002% of full scale per ºC
Response time: Step response: 300 milliseconds
  With range change 250 milliseconds per range
Commom mode rejection: AC, 61Hz and below 94dB with up to 100 Ohm in either lead
Input resistance (all rages):   1 Megohm in series with 0.22 microfarad
Shunt capacitance at terminals: less than 200pF, all ranges
     
OHMS MEASUREMENTS    
Maximum voltage across unknown: 10V at full scale, max current 10mA on 1kohm range
 Full scale ranges   1.09999, 10.9999, 109.999, 1099.99, 1099.9 kohms
Accuracy, 3 months: 1, 10, 100 kilohms range: ±0.01% of reading ±0.001% full scale
  1000 kilohms range: ±0.03% of reading ±0.001% full scale
  10,000 kilohms range: ±0.1% of reading ±0.001% full scale
Temperature coefficient: 1, 10, 100 kilohms range: ±0.002% of reading ±0.0002% full scale
  1000 kilohms range: ±0.0035% of reading ±0.0002% full scale
  10,000 kilohms range: ±0.005% of reading ±0.001% full scale
Response time: Step response 750msec
  With range change 750msec/range
     
GENERAL SPECIFICATIONS    
Operating temperature range: -40ºC to +55ºC (internal temp. remains above +15ºC
Maximum power requirement:   50W, 105 to 125V (export 210 to 250V)
    50 to 70Hz (400Hz special)
Maximum commom mode voltage:   250 volts
Dimensions:   Standard 19-inch rack width; 5-1/4 high
Guarantee:   12 months, faulty workmanship or component failure

 

 

HOMETEST EQBRANDED GIGSUPVP-526A