A few years ago I had an HP 8116A Pulse Function generator given to me, which is nice seeing as how they still go (even at 15 years old or so) for over $2,000. Unfortunately for me theres a problem with it, when it comes on and does a P.O.S.T. it returns E21, and I get nothing from the output. Recently I dug it out of the closet because I thought maybe I should try to get it working, so I did some searching online and found that E21 means "Fault in the internal repetition rate generator" I'm no expert but I would think the repetition rate generator has to do with controlling the pulse waveform portion of this unit, and wouldn't effect the sine/square/etc. Maybe (more like probably) I'm wrong. I guess what I'm getting at is: does anyone out there have any experience repairing function generators, or know a lot about them that might be able to help me get this thing working.
cheers,
Daniel
cheers,
Daniel
hmmm, you might be on to something here I opened her up and looked around, I didnt see any caps that were obviously blown or oozing yummy yellow snot, but I did find a battery, I through a DMM on it, and it reads 1.05V, I googled some numbers printed on the battery and found out that the battery is a 2.5V NiCd battery, do you think that this much of a power loss could be causing problems? Check out this picture here (if the link doesnt work let me know, its the first time I've tried to link to picasa) notice the corrosion on the terminals. 8116A Battery
thanks for the response,
Daniel
thanks for the response,
Daniel
new information; I managed to find an excerpt of the service manual online regarding battery failure it reads: "If the instrument RAM becomes corrupted due to battery failure, the Standard Paramater Set will be selected when the instrument is first turned on, in order to give an error free display"
After reading this I dont think my problem could be caused by battery failure, as it seems to mantain programming, even if the battery fails, it just wont mantain the same settings if the power is disconnected. Thats what I get from that passage anyway, what are your ideas?
After reading this I dont think my problem could be caused by battery failure, as it seems to mantain programming, even if the battery fails, it just wont mantain the same settings if the power is disconnected. Thats what I get from that passage anyway, what are your ideas?
Before flash memory was invented, batteries were a popular way of providing continous power for a RAM memory. What was in the RAM? Likely it held calibration coefficients. So the microproceesor goes there and the numbers are gone, then flags an error. The rate generator probably needs numbers to correct the oscillator
How do you fix it? Send it to HP. More than likely... it is a paperweight now.
You could try replacing the battery... don't get your hopes up. If you do decide to... its complicated.
1) Get a new battery.
2) Measure the old battery's voltage in circuit.
3) Set a DC supply to this exact voltage.
4) Connect the supply to the circuit... there might be a place to plug in for this... otherwise you'll have to tack some wires on the board.
5) With power in place... remove the old battery.
6) Increase the supply voltage to equal the voltage of the new battery.
7) Install the new battery.
8) Remove the power supply.
The idea behind all of this is to keep power to the RAM chips at all times. And, also not to set the lithiums on fire by mismatching a parallel supply.
Before you spend the $10 on the battery... find the RAM chips and look up the spec for minimum voltage to ensure data retention. Sorry but 1.05 volts sounds way low... you are probably hosed.
Check HP's site (Agilent) and see if they still support it and how much a service costs.
Been here, done this...
How do you fix it? Send it to HP. More than likely... it is a paperweight now.
You could try replacing the battery... don't get your hopes up. If you do decide to... its complicated.
1) Get a new battery.
2) Measure the old battery's voltage in circuit.
3) Set a DC supply to this exact voltage.
4) Connect the supply to the circuit... there might be a place to plug in for this... otherwise you'll have to tack some wires on the board.
5) With power in place... remove the old battery.
6) Increase the supply voltage to equal the voltage of the new battery.
7) Install the new battery.
8) Remove the power supply.
The idea behind all of this is to keep power to the RAM chips at all times. And, also not to set the lithiums on fire by mismatching a parallel supply.
Before you spend the $10 on the battery... find the RAM chips and look up the spec for minimum voltage to ensure data retention. Sorry but 1.05 volts sounds way low... you are probably hosed.
Check HP's site (Agilent) and see if they still support it and how much a service costs.
Been here, done this...
Howdy - I have an 8116A, which had an intermittent signal problem. Managed to trace this to one of the small-signal transistors. Never did find an exact replacement, but the unit works, with perhaps a degradation in speed.
Anyway, the manual from the Agilent website unfortunately doesn't include any information on how to service the "E" code errors. It's supposed to be in Chapter 10.1, but the downloadable manual ends at chapter 9.
The manual does say that the battery is only used to "remember" the last operating parameters, but I guess taking out the battery, letting the unit sit idle for some time and turning it back on should reset the RAM to uninitialized state - if the error code persists it's time to ask Agilent for the rest of the chapters!!
Cheers
Clem
Anyway, the manual from the Agilent website unfortunately doesn't include any information on how to service the "E" code errors. It's supposed to be in Chapter 10.1, but the downloadable manual ends at chapter 9.
The manual does say that the battery is only used to "remember" the last operating parameters, but I guess taking out the battery, letting the unit sit idle for some time and turning it back on should reset the RAM to uninitialized state - if the error code persists it's time to ask Agilent for the rest of the chapters!!
Cheers
Clem
clem_o said:
I think I'll make this my next course of action, I'm not thrilled with the idea of removing the battery as it's soldered in, but I suppose to reinstall it I could solder leads to the PCB and use a battery holder, might be an idea there. on a side note, the +5V lead that goes to the PCB next to the battery broke off lastnight, that was a fun one to solder
I'll give Agilent a call, and I'll keep you posted on the progress
cheers,
Daniel
PS If I manage to get a manual (including chapter 10) from Agilent I'll send you a copy.
I know this is an ancient discussion, but perhaps this might still be of interest. The link has a description on replacing the ni-cad battery in an HP 8116A. Scroll down to find the discussion.
http://www.cliftonlaboratories.com/july_2007.htm
I don't know if doing this will correct the errors you guys are seeing or not, but from the discussion it seems that replacing the battery does not erase any calibration factors required for the signal generator to operate.
Looking through the 8116A service manual, calibration looks to be done entirely by means of pots and jumpers anyway.
http://www.cliftonlaboratories.com/july_2007.htm
I don't know if doing this will correct the errors you guys are seeing or not, but from the discussion it seems that replacing the battery does not erase any calibration factors required for the signal generator to operate.
Looking through the 8116A service manual, calibration looks to be done entirely by means of pots and jumpers anyway.
I found this link, wich might be the missing pages you were stated in your post:
http://techpreservation.dyndns.org/beitman/abpr/newfiles/HP8116A Service.pdf
so hope it might be helpfull
Best regards from France.
Largol.
http://techpreservation.dyndns.org/beitman/abpr/newfiles/HP8116A Service.pdf
so hope it might be helpfull
Best regards from France.
Largol.
I just received my HP 8116A unit and have the E21 error, so I planned to open the unit but I have trouble opening the top cover !!!
How do you manage to open the cover ?
From what I read there's this procedure (from the service manual):
For frequencies up to 999 kHz the Schmitt-trigger levels are set
at 0 V for the low level (U201 pin 14) and 2 V for the high level
(U201 pin 15). Hence the timing-capacitor voltage on pin 12 of U201
varies between 0 and 2 V as shown in Figure 10.3-9.
If the levels are incorrect:
1. Switch off the HP 8116A.
2. Remove the VCO (slope) IC U201.
3. Switch on the HP 8116A and press (LCL) to reset error E21.
4. Check that the voltages supplied to pins 14 and 15 of U201's IC
socket are correct.
5. If not, check the analog switch U205 against Table 10.3-9:
Well, at least maybe this VCO is the culprit in getting error E21.
Hope, I don't have to replace it, cos it seems to be an old fashioned IC!
let me know your thoughs
Best Regards.
Largol
How do you manage to open the cover ?
From what I read there's this procedure (from the service manual):
For frequencies up to 999 kHz the Schmitt-trigger levels are set
at 0 V for the low level (U201 pin 14) and 2 V for the high level
(U201 pin 15). Hence the timing-capacitor voltage on pin 12 of U201
varies between 0 and 2 V as shown in Figure 10.3-9.
If the levels are incorrect:
1. Switch off the HP 8116A.
2. Remove the VCO (slope) IC U201.
3. Switch on the HP 8116A and press (LCL) to reset error E21.
4. Check that the voltages supplied to pins 14 and 15 of U201's IC
socket are correct.
5. If not, check the analog switch U205 against Table 10.3-9:
Well, at least maybe this VCO is the culprit in getting error E21.
Hope, I don't have to replace it, cos it seems to be an old fashioned IC!
let me know your thoughs
Best Regards.
Largol
Well, today, I made what was written on the service manual:
I removed the U201 IC, it's the custom VCO by H.P.
Then restarted the unit, the pressed LCL key.
Error E21 dispeared !
I said myself, great you're done ....
I unplug the unit, put back the VCO (was nearly to broke a few leads from the IC
And then, when I power the unit once again, there was absolutely no display.
So I have to investigate....
But with the link I provided, you have the complete service manual, including all schematics and procedures issued from H.P.
Time to go back investigating, wish me good luck!
I removed the U201 IC, it's the custom VCO by H.P.
Then restarted the unit, the pressed LCL key.
Error E21 dispeared !
I said myself, great you're done ....
I unplug the unit, put back the VCO (was nearly to broke a few leads from the IC
And then, when I power the unit once again, there was absolutely no display.
So I have to investigate....
But with the link I provided, you have the complete service manual, including all schematics and procedures issued from H.P.
Time to go back investigating, wish me good luck!
Largol said:
try this group, it seems to be the brain trust for how to fix HP equipment.
http://tech.groups.yahoo.com/group/hp_agilent_equipment/
Well the +5.1 Volts line was working fine on main PCB board, but red wire didn't carry out the power to the microprocessor board, hence no power up sequence and no display.
So I fixed it, and I now have display and once again the E21 error.
Seems that the VCO circuit is the culrit, needs to check the pin 14 (i.e. 0 Volts) and Pin 15 (i.e. 2 Volts) and the manual
I will find the error!
So I fixed it, and I now have display and once again the E21 error.
Seems that the VCO circuit is the culrit, needs to check the pin 14 (i.e. 0 Volts) and Pin 15 (i.e. 2 Volts) and the manual
I will find the error!
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