Meter taylor 45B - UK Vintage Radio Repair and Restoration Discussion Forum

peppe66 · 19th May 2005, 3:25 pm

Hi to everybody,
I have a problem with a Taylor 45B.
The readings are correct on all the positions however on the positions cathode leakage and mutual conductance, the needle of the tool enters vibration.
Has someone had this problem? How can you/he/she be resolved? eliminating the diode of protection?

Thanks
Joseph

Ed_Dinning · 19th May 2005, 5:16 pm

Hi Joseph, it could be hum on the power supply, as a larger current is drawn on the emmission test and it will show up more. Look at replacing the caps on the high voltage supply, or bridge them temoprarily with a similar value and see if the problem goes away.

Ed

retailer · 23rd May 2005, 6:43 am

Hi I've repaired two of these now and things to look for are. 1. dirty switch contacts, clean them all with a good quality contact cleaner. and 2. Overheated/damaged wire wound pots for grid and both A and B controls. If you need to replace the A pot get a good quality 10 turn pot makes setting A much easier ( you can find them on Ebay). I hav'nt come across out of tolerance resistors, and there are no smoothing caps to worry about. You can check voltages by setting up a valve test for GM without plugging the valve in. With the valve pin connections in front of you measure from the black socket on top to the various pins and confirm the voltages (AC) are correct. For say a 6V6 you should have about 100V on pin 3 and about 100v on pin 4. Pin 5 voltage should vary smoothly with the grid control. Pin 8 cathode should be 0v. Pins are numbered anti-clockwise when looked at from above. If you're not getting correct voltages you'll need to trace back through the switches. Looking at the circuit SW3/4F means switch 3, wafer 4, Front contacts (contacts nearest the front panel). There may be two capacitors fitted to one of the switches check these for shorts
Hope this helps

peppe66 · 23rd May 2005, 7:35 am

Thanks for the help guy's,
therefore I have changed all the capacitor's, I have cleaned the contacts and I have changed all the resistor out value.
The vibration is decreased a lot, but however she remains (it imperceptibly vibration now only the point of the needle of the meter).
The pot A is not precise in the regulation (it "jumps" in some point), I have to change it.
The tensions are correct, and making a comparison with a The-177B the readings are correct.

Can she be a problem of transformer?

Best regards from Italy
Joseph

retailer · 23rd May 2005, 10:05 pm

Hi
I don't think it is the transformer. If the transformer was faulty it probably would'nt work at all. Here is a quote from the manual

"Note c); If the meter pointer is seen to be vibrating this is due to unrectified A.C. across the meter circuit and is probably caused by internal short in the valve under test. The instrument should be switched off immediately to avoid damage to the meter, or the main selector can be turned back to Cathode Leakage"

Incorrect settings or shorted valves will cause needle vibrations. Once I tried a shorted valve in mine and the needle vibrationed at least 1cm

Here is another quote from the manual

"When the anode and screen voltages are negative the grid voltage is zero and no meter current passes. The inertia of the meter causes it to read steadily although the current through it is intermittent."

I don't have time at the moment but tonite will check to see if the needle is rock steady or vibrates imperceptiby.
Regards Zenon

peppe66 · 24th May 2005, 10:06 am

Thanks endless Retailer,
if you can check if also on yours there is a light vibration of the needle in mutual conductance position I would be thankful of it.
I think that a light vibration is normal, and I hope that she don't damage the meter.

Regards
Joseph

retailer · 25th May 2005, 3:00 pm

Hi I've finally found the time to check it, and if it is vibrating then I can't see it, the pointer is not blurred at all.
Does it happen with all valves, maybe the ones you are testing have leakage and are passing ac to the meter. Have you checked with no valve plugged in and A control fully advanced. If there is a faulty part or wiring in your tester causing AC on the meter then the fault would still be there with no valve plugged in. If the fault appears after a valve is plugged in, it may be the valve. One other thing - have you checked the grid voltage rectifier, these are the sellenium type and being old may be leaky allowing AC on the grid, which is amplified by the valve. I have replaced mine with a small silicone diode
Quote from the manual
"MUTUAL CONDUCTANCE
In this test a choice of anode screen and grid voltages is provided These are A.C. except that the grid voltage is prevented from going positive by a small rectifier. The transformer windings are phased so that the anode and screen voltages are in phase whilst the grid voltage is out of phase"
I have replaced mine with a small silicone diode.
The Taylor is a good tester and the readings on mine agree fairly closely with my home made Steve Bench designed GM/Mu tester
Regards Zenon

peppe66 · 25th May 2005, 6:28 pm

Hi Retailer,
thanks for the help.
Therefore I have changed the rectifier, but I have not gotten improvements.
I have made another test instead; I have momentarily connected another meter to the place of the original one and this works very well.
Therefore it is a problem of the meter.
If I wanted to replace it, that characteristics he should have? How much mA f.s he should have?

Best regards

Joseph

peppe66 · 26th May 2005, 8:54 am

Hi,
believes to have understood the problem.
it is a problem of balancing of the needle.
It was out center the axle on the antagonists springs and this provoked a vibration of the springs same that it transmitted him to the needle when it overcame halves the scale.
It is everything ok now... she can be made up for with the small screw on the same axle.
If someone has the same problem this discussion she can be of help.
Thanks to Retailer for the precious help.

Best regards
Joseph

retailer · 26th May 2005, 1:13 pm

Hi Joseph
It's good to see all has ended well. My first valve tester an Eico 666 arrived from USA not working at all. The meter needle had snapped off in the past and some one had soldered the pointer end back on to the coil assembly, balance was out, meter was either full scale or nothing, could'nt figure it out at first. Managed to unsolder it clean it up reattach it and balance it. After fixing a few other problems ( a switch wired incorrectly , maybe by a kit builder) it worked. I was hooked, I just can't keep away from old valve testers now. I've had 5 since then and at the moment a Taylor 45B and my excellent DIY tester which reads true GM and Mu at full operating voltages.
I guess I assumed that the vibration was 50hz that would have caused the needle to look blurred. In case you need to know for the future my meter is near enough to 220 uA/90 ohms. Good luck with your tester.

peppe66 · 27th May 2005, 9:52 am

Hi Retailer,
in fact, the vibration of the needle was mainly due to the 50 Hz of the electric net, and since the needle and the spool were very loosened, it provoked the vibration of the springs antagonists and therefore of the point of the needle.
With the regulation of the brake on the axle of the spool, the defect has disappeared and the tube tester now works to wonder.
Who knows if feeding it with a filtered power outlet a greater improvement is gotten.
What do you say of it?

Regards

Joseph

retailer · 27th May 2005, 9:56 pm

Maybe a powerline conditioner to filter out RF and voltage surges might help but I doubt it. I took my tester to work to test some valves I picked up at a local salvage yard and I noticed nothing when our large compressors were stopping and starting (the lights dim when they start). I say If its working to your satisfaction put the cover back and leave it now.
Can you test el84? I had to make an adaptor as I could'nt find an ABC setting that would work.

peppe66 · 28th May 2005, 5:42 pm

Hi, I have never made a will an EL84.
but it seems me that on 45B it misses the position of the command B for the pins 9 - 1 (respectively screen/IC)
The only solution is an adapter that reverses the position of the pins when the B is on 5 (from 1-9 to 9 - 1)

this way it would be had:
6,3 (filament)
250/200 (anode - screen)
7 (g1)
554 (ABC with the inverted pins of the B)
I hope not to have said stupidities...... everything to be tried

retailer · 29th May 2005, 6:08 am

Hi Joseph
Yes I reckon that would work, problem I found was some pins are marked ic. For some makers this means internal connection and for others it means no connection, so I left these pins unconnected in my adaptor and copied 6V6 pin connections with el84 plate to 6v6 plate etc and then used the 6V6 ABC switch settings. It means that this adaptor can only be used with el84 as 3 pins are left unconnected.

19th May 2005, 3:25 pm	#1
peppe66 Retired Dormant Member Join Date: Apr 2005 Posts: 7	Meter taylor 45B Hi to everybody, I have a problem with a Taylor 45B. The readings are correct on all the positions however on the positions cathode leakage and mutual conductance, the needle of the tool enters vibration. Has someone had this problem? How can you/he/she be resolved? eliminating the diode of protection? Thanks Joseph

19th May 2005, 5:16 pm	#2
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Meter taylor 45B Hi Joseph, it could be hum on the power supply, as a larger current is drawn on the emmission test and it will show up more. Look at replacing the caps on the high voltage supply, or bridge them temoprarily with a similar value and see if the problem goes away. Ed

23rd May 2005, 6:43 am	#3
retailer Heptode Join Date: May 2005 Location: Adelaide, South Australia Posts: 541	Re: Meter taylor 45B Hi I've repaired two of these now and things to look for are. 1. dirty switch contacts, clean them all with a good quality contact cleaner. and 2. Overheated/damaged wire wound pots for grid and both A and B controls. If you need to replace the A pot get a good quality 10 turn pot makes setting A much easier ( you can find them on Ebay). I hav'nt come across out of tolerance resistors, and there are no smoothing caps to worry about. You can check voltages by setting up a valve test for GM without plugging the valve in. With the valve pin connections in front of you measure from the black socket on top to the various pins and confirm the voltages (AC) are correct. For say a 6V6 you should have about 100V on pin 3 and about 100v on pin 4. Pin 5 voltage should vary smoothly with the grid control. Pin 8 cathode should be 0v. Pins are numbered anti-clockwise when looked at from above. If you're not getting correct voltages you'll need to trace back through the switches. Looking at the circuit SW3/4F means switch 3, wafer 4, Front contacts (contacts nearest the front panel). There may be two capacitors fitted to one of the switches check these for shorts Hope this helps

23rd May 2005, 7:35 am	#4
peppe66 Retired Dormant Member Join Date: Apr 2005 Posts: 7	Re: Meter taylor 45B Thanks for the help guy's, therefore I have changed all the capacitor's, I have cleaned the contacts and I have changed all the resistor out value. The vibration is decreased a lot, but however she remains (it imperceptibly vibration now only the point of the needle of the meter). The pot A is not precise in the regulation (it "jumps" in some point), I have to change it. The tensions are correct, and making a comparison with a The-177B the readings are correct. Can she be a problem of transformer? Best regards from Italy Joseph

23rd May 2005, 10:05 pm	#5
retailer Heptode Join Date: May 2005 Location: Adelaide, South Australia Posts: 541	Re: Meter taylor 45B Hi I don't think it is the transformer. If the transformer was faulty it probably would'nt work at all. Here is a quote from the manual "Note c); If the meter pointer is seen to be vibrating this is due to unrectified A.C. across the meter circuit and is probably caused by internal short in the valve under test. The instrument should be switched off immediately to avoid damage to the meter, or the main selector can be turned back to Cathode Leakage" Incorrect settings or shorted valves will cause needle vibrations. Once I tried a shorted valve in mine and the needle vibrationed at least 1cm Here is another quote from the manual "When the anode and screen voltages are negative the grid voltage is zero and no meter current passes. The inertia of the meter causes it to read steadily although the current through it is intermittent." I don't have time at the moment but tonite will check to see if the needle is rock steady or vibrates imperceptiby. Regards Zenon

24th May 2005, 10:06 am	#6
peppe66 Retired Dormant Member Join Date: Apr 2005 Posts: 7	Re: Meter taylor 45B Thanks endless Retailer, if you can check if also on yours there is a light vibration of the needle in mutual conductance position I would be thankful of it. I think that a light vibration is normal, and I hope that she don't damage the meter. Regards Joseph

25th May 2005, 3:00 pm	#7
retailer Heptode Join Date: May 2005 Location: Adelaide, South Australia Posts: 541	Re: Meter taylor 45B Hi I've finally found the time to check it, and if it is vibrating then I can't see it, the pointer is not blurred at all. Does it happen with all valves, maybe the ones you are testing have leakage and are passing ac to the meter. Have you checked with no valve plugged in and A control fully advanced. If there is a faulty part or wiring in your tester causing AC on the meter then the fault would still be there with no valve plugged in. If the fault appears after a valve is plugged in, it may be the valve. One other thing - have you checked the grid voltage rectifier, these are the sellenium type and being old may be leaky allowing AC on the grid, which is amplified by the valve. I have replaced mine with a small silicone diode Quote from the manual "MUTUAL CONDUCTANCE In this test a choice of anode screen and grid voltages is provided These are A.C. except that the grid voltage is prevented from going positive by a small rectifier. The transformer windings are phased so that the anode and screen voltages are in phase whilst the grid voltage is out of phase" I have replaced mine with a small silicone diode. The Taylor is a good tester and the readings on mine agree fairly closely with my home made Steve Bench designed GM/Mu tester Regards Zenon

25th May 2005, 6:28 pm	#8
peppe66 Retired Dormant Member Join Date: Apr 2005 Posts: 7	Re: Meter taylor 45B Hi Retailer, thanks for the help. Therefore I have changed the rectifier, but I have not gotten improvements. I have made another test instead; I have momentarily connected another meter to the place of the original one and this works very well. Therefore it is a problem of the meter. If I wanted to replace it, that characteristics he should have? How much mA f.s he should have? Best regards Joseph

26th May 2005, 8:54 am	#9
peppe66 Retired Dormant Member Join Date: Apr 2005 Posts: 7	Re: Meter taylor 45B Hi, believes to have understood the problem. it is a problem of balancing of the needle. It was out center the axle on the antagonists springs and this provoked a vibration of the springs same that it transmitted him to the needle when it overcame halves the scale. It is everything ok now... she can be made up for with the small screw on the same axle. If someone has the same problem this discussion she can be of help. Thanks to Retailer for the precious help. Best regards Joseph

26th May 2005, 1:13 pm	#10
retailer Heptode Join Date: May 2005 Location: Adelaide, South Australia Posts: 541	Re: Meter taylor 45B Hi Joseph It's good to see all has ended well. My first valve tester an Eico 666 arrived from USA not working at all. The meter needle had snapped off in the past and some one had soldered the pointer end back on to the coil assembly, balance was out, meter was either full scale or nothing, could'nt figure it out at first. Managed to unsolder it clean it up reattach it and balance it. After fixing a few other problems ( a switch wired incorrectly , maybe by a kit builder) it worked. I was hooked, I just can't keep away from old valve testers now. I've had 5 since then and at the moment a Taylor 45B and my excellent DIY tester which reads true GM and Mu at full operating voltages. I guess I assumed that the vibration was 50hz that would have caused the needle to look blurred. In case you need to know for the future my meter is near enough to 220 uA/90 ohms. Good luck with your tester.

27th May 2005, 9:52 am	#11
peppe66 Retired Dormant Member Join Date: Apr 2005 Posts: 7	Re: Meter taylor 45B Hi Retailer, in fact, the vibration of the needle was mainly due to the 50 Hz of the electric net, and since the needle and the spool were very loosened, it provoked the vibration of the springs antagonists and therefore of the point of the needle. With the regulation of the brake on the axle of the spool, the defect has disappeared and the tube tester now works to wonder. Who knows if feeding it with a filtered power outlet a greater improvement is gotten. What do you say of it? Regards Joseph

27th May 2005, 9:56 pm	#12
retailer Heptode Join Date: May 2005 Location: Adelaide, South Australia Posts: 541	Re: Meter taylor 45B Maybe a powerline conditioner to filter out RF and voltage surges might help but I doubt it. I took my tester to work to test some valves I picked up at a local salvage yard and I noticed nothing when our large compressors were stopping and starting (the lights dim when they start). I say If its working to your satisfaction put the cover back and leave it now. Can you test el84? I had to make an adaptor as I could'nt find an ABC setting that would work.

28th May 2005, 5:42 pm	#13
peppe66 Retired Dormant Member Join Date: Apr 2005 Posts: 7	Re: Meter taylor 45B Hi, I have never made a will an EL84. but it seems me that on 45B it misses the position of the command B for the pins 9 - 1 (respectively screen/IC) The only solution is an adapter that reverses the position of the pins when the B is on 5 (from 1-9 to 9 - 1) this way it would be had: 6,3 (filament) 250/200 (anode - screen) 7 (g1) 554 (ABC with the inverted pins of the B) I hope not to have said stupidities...... everything to be tried

29th May 2005, 6:08 am	#14
retailer Heptode Join Date: May 2005 Location: Adelaide, South Australia Posts: 541	Re: Meter taylor 45B Hi Joseph Yes I reckon that would work, problem I found was some pins are marked ic. For some makers this means internal connection and for others it means no connection, so I left these pins unconnected in my adaptor and copied 6V6 pin connections with el84 plate to 6v6 plate etc and then used the 6V6 ABC switch settings. It means that this adaptor can only be used with el84 as 3 pins are left unconnected.