I've done searches on
Tube & Test & Set & Calibration
Mercury & 1000 & Tube & Test & Set & Calibration
Etc....
Anyone have any suggestions on calibrating a Mercury 1000/2000 test set?
I've got the schematic, user manual, etc.🙂
No calibration info though.😡
Thanks.
Steven
Tube & Test & Set & Calibration
Mercury & 1000 & Tube & Test & Set & Calibration
Etc....
Anyone have any suggestions on calibrating a Mercury 1000/2000 test set?
I've got the schematic, user manual, etc.🙂
No calibration info though.😡
Thanks.
Steven
I've done searches on
Tube & Test & Set & Calibration
Mercury & 1000 & Tube & Test & Set & Calibration
Etc....
Anyone have any suggestions on calibrating a Mercury 1000/2000 test set?
I've got the schematic, user manual, etc.🙂
No calibration info though.😡
Thanks.
Steven
I could have swore there was cali info in the manual, if memory serves it requires the use of a specific tube as well. I have that model, I'll check later for the info.
OK,
I have the Merc 2000. The calibration info is in the user manual.
I made it downloadable since the attachment button on here messes up the size/scan
Mercury 2000 calibration instructions
It does show using a 6BA6 tube during the process, when I bought mine, it still had the original cal tube in the box.
I have the Merc 2000. The calibration info is in the user manual.
I made it downloadable since the attachment button on here messes up the size/scan
Mercury 2000 calibration instructions
It does show using a 6BA6 tube during the process, when I bought mine, it still had the original cal tube in the box.
Thanks.
1000 does not have cal procedure in manual, but I have a late 1000 that is like the 2000 w/o the transistor test circuit.
So, the info should apply.
1000 does not have cal procedure in manual, but I have a late 1000 that is like the 2000 w/o the transistor test circuit.
So, the info should apply.
I've been trying to go through the cal procedure and it looks like there is something wrong but I'm at a loss as to what.
I've got three 6BA6s that read over 4200Gm to work with, and I can build a test set to bias them and measure the actual GM at data sheet specs if necessary for reference.
The DC Bias is only -3.2V instead of the -5.9 in the schematic. The signal is only 0.68Vrms instead of 1V, unless it is supposed to be 1V peak in which case it is close.
1. Preliminary setup is fine.
2. Zero Cal is fine
3. Meter Sensitivity Cal has the meter going negative and not adjustable.
I checked both diodes (D2 and D3) thinking one might be out and causing an imbalance, but they are fine.
Both lamps B2 and B3 are OK.
Anyone have any suggestions?
tks
Steven
I've got three 6BA6s that read over 4200Gm to work with, and I can build a test set to bias them and measure the actual GM at data sheet specs if necessary for reference.
The DC Bias is only -3.2V instead of the -5.9 in the schematic. The signal is only 0.68Vrms instead of 1V, unless it is supposed to be 1V peak in which case it is close.
1. Preliminary setup is fine.
2. Zero Cal is fine
3. Meter Sensitivity Cal has the meter going negative and not adjustable.
I checked both diodes (D2 and D3) thinking one might be out and causing an imbalance, but they are fine.
Both lamps B2 and B3 are OK.
Anyone have any suggestions?
tks
Steven
I found a 270Ohm resistor open (R20), and in the cal procedure the diode is backwards in 3.b
The test set now cal's properly.
I'm getting good readings and good voltages on the pins (using a tube extender with test points), except for tubes with topcaps. No dc on them so I've still got work to go. Strange thing is the Gm shows good on those tubes even though I'm not getting DC on the caps.
The test set now cal's properly.
I'm getting good readings and good voltages on the pins (using a tube extender with test points), except for tubes with topcaps. No dc on them so I've still got work to go. Strange thing is the Gm shows good on those tubes even though I'm not getting DC on the caps.
I found a bad tube extender contact was causing problems.
It looks like everything is OK now, except I've got a couple of resistors out of spec.
I got 20 6P1P-EV tubes in the mail this morning. Tested all 20 and they all tested good.
Selector D
Load 90
Socket 6
G - 7
P - 1/2/6/9
Gm 3700** (Low Scale)
Low Gm3900 (2), High Gm 4900(2), The remainder were between 4100 and 4400Gm.
Hopefully this info will help someone else in the future.
Now to design a PP amp with 6P1P-EVs. I'll use 6N2P-3Vs as unity gain phase splitters/drivers. Probably 6SN7s (for low noise) as first amp stage to drive the 6N2P-EVs.
I've got Hammond 1609 transformers on order for the outputs, and a old Stancor power transformer (dual 300V 120ma windings plus 5V and 6.3V) for power.
Steven
It looks like everything is OK now, except I've got a couple of resistors out of spec.
I got 20 6P1P-EV tubes in the mail this morning. Tested all 20 and they all tested good.
Selector D
Load 90
Socket 6
G - 7
P - 1/2/6/9
Gm 3700** (Low Scale)
Low Gm3900 (2), High Gm 4900(2), The remainder were between 4100 and 4400Gm.
Hopefully this info will help someone else in the future.
Now to design a PP amp with 6P1P-EVs. I'll use 6N2P-3Vs as unity gain phase splitters/drivers. Probably 6SN7s (for low noise) as first amp stage to drive the 6N2P-EVs.
I've got Hammond 1609 transformers on order for the outputs, and a old Stancor power transformer (dual 300V 120ma windings plus 5V and 6.3V) for power.
Steven
Hello: I have a Mercury 2000 tube tester too!! I need to find out where I can buy the 500 ma 100 piv silicon rectifier used to calibrate the meter sensitivity. Can you help?? Thanks, Alex
Since the cal procedure specifies Silicon or Selenium as the rectifier, it is not critical.
I suggest a 1N4002, 3, 4, 5, 6, or 7.
I used a 1N4007 as I have a bunch.
I suggest a 1N4002, 3, 4, 5, 6, or 7.
I used a 1N4007 as I have a bunch.
I need to open my 2000 and check it out good.
Lately I am getting what I'll call meter float.
No matter what type of tube I check, new production, old tubes, nos and so on the meter never settles in. I get a pretty wide fluctuation in the readings.
Maybe its just line fluctuations?
I still have the original calibration tube that came with the meter, but most certainly the unit is getting up there in age and may need a few parts.
Lately I am getting what I'll call meter float.
No matter what type of tube I check, new production, old tubes, nos and so on the meter never settles in. I get a pretty wide fluctuation in the readings.
Maybe its just line fluctuations?
I still have the original calibration tube that came with the meter, but most certainly the unit is getting up there in age and may need a few parts.
Mercury 2000 Tube Tester
Thanks for the responses leading me to the 1N4002 silicon rectifier needed to perform the meter sensitivity calibration check. Having done some more research once I had that info, it appears that the reason you can use any of the 1N4000 series rectifiers is that they all exhibit a 0.7 forward voltage drop which is typical of rectifiers and very constant regardless of normal room temperatures. The circuit designers, most likely, are using the 0.7 V silicon rectifier voltage drop as a reference for calibration.
The intermittant performance experienced with the Mercury 2000 tester is most likely due to electrolytic capacitors that need to be replaced. All four in mine were shot. To make it easy to find the replacement parts, here is the info: Supplier Mouser Electronics:
250uF 16V Electrolytic, part # 75-TVA1161
100uF 25V Electrolytic part # 647-TVX1E101MAD
while you are at it, you might as well order from Mouser the .02 uF 2000V ceramic capacitor, which was a pain in the neck to find. That part # is: 75-564RZ5UAA202EP203. All of the other replacement parts you may need for the circuit board are more readily available. Yep, I would order a new tube for the inside and two of the calibration tubes. Shipping charges are so high these days you need to order whatever you need all at once; if you can.
Good Luck, and once again thanks to both responders who were good enough to respond when I needed help.
Thanks for the responses leading me to the 1N4002 silicon rectifier needed to perform the meter sensitivity calibration check. Having done some more research once I had that info, it appears that the reason you can use any of the 1N4000 series rectifiers is that they all exhibit a 0.7 forward voltage drop which is typical of rectifiers and very constant regardless of normal room temperatures. The circuit designers, most likely, are using the 0.7 V silicon rectifier voltage drop as a reference for calibration.
The intermittant performance experienced with the Mercury 2000 tester is most likely due to electrolytic capacitors that need to be replaced. All four in mine were shot. To make it easy to find the replacement parts, here is the info: Supplier Mouser Electronics:
250uF 16V Electrolytic, part # 75-TVA1161
100uF 25V Electrolytic part # 647-TVX1E101MAD
while you are at it, you might as well order from Mouser the .02 uF 2000V ceramic capacitor, which was a pain in the neck to find. That part # is: 75-564RZ5UAA202EP203. All of the other replacement parts you may need for the circuit board are more readily available. Yep, I would order a new tube for the inside and two of the calibration tubes. Shipping charges are so high these days you need to order whatever you need all at once; if you can.
Good Luck, and once again thanks to both responders who were good enough to respond when I needed help.
I find, when check for efectiveness of re-calibrating tube testers, if you also use a bais probe, you can confirm the accuracy using simple math. You can measure your units voltage, the probe with give you the current, do the math, compare to your meter. You can either use a bias probe with bias meter. Just take note where the 1 ohm resistor should be depending on which tube socket you use.
Mercury 2000 calibration
I new to this forum, came across this thread in a search.
I'm confused about the 6BA6 with a "rated Gm of 4300" being used for the calibration procedure. When the tube charts actually show the rated Gm of a 6BA6 as 4000. Anyone?
I new to this forum, came across this thread in a search.
I'm confused about the 6BA6 with a "rated Gm of 4300" being used for the calibration procedure. When the tube charts actually show the rated Gm of a 6BA6 as 4000. Anyone?
Because they provided a selected tube with a known Gm with the tube tester, specifically for calibration.
They then specify calibrating the tube tester to 4200-4300.
It should not matter what the Gm of the tube is (within reason) as long as the Gm is known you can calibrate the test set to it.
They then specify calibrating the tube tester to 4200-4300.
It should not matter what the Gm of the tube is (within reason) as long as the Gm is known you can calibrate the test set to it.
So my question is if the 6BA6 has a known Gm of 4300 then why would the tube data supplied with the unit specify a Gm of 4000 for testing the 6BA6? And 4200-4300 for calibration?Is it another error like the diode polarity another member noticed in the cal procedure?
That, or due to the inherent lack of precision they do a corrected calibration to get the most tube types to come out right in that scale.
Can you re-send this link for Mercury Model 202 calibration and grant me access please? It won't authorize me to open it.
(Do you mean "202"? Or "2000"?
Trout has not been here in years.
A simple web search turns up this:
https://vintagetubeelectronics.com/wp-content/uploads/2019/03/Mercury-2000-Users-Manual.pdf
Is that what you want?
Oh, fah. The PDF is small enough to post here.