Hi,
Need some help with my hp6227b dc power supply. Just got this and when running through the switch on procedure which is.
1. Turn volts / amps selector switches to volts
2. Turn tra king / independent selection switch to independent
3. Turn crowbar adjust to full clockwise posistion
4. Turn current potentiometers to their middle position
5. Switch on.
Having followed this procedure the power supply switched on and functioned. The left hand output however will only snowed out 15 volts when its turned fully right instead of 25 volts. The left hand output gives out a full 25 volts.
Also when the selector switch is then changed to amps, both channels do not react when turning the potentiometers.
Can anyone point me in the right direction? Thanks.
Need some help with my hp6227b dc power supply. Just got this and when running through the switch on procedure which is.
1. Turn volts / amps selector switches to volts
2. Turn tra king / independent selection switch to independent
3. Turn crowbar adjust to full clockwise posistion
4. Turn current potentiometers to their middle position
5. Switch on.
Having followed this procedure the power supply switched on and functioned. The left hand output however will only snowed out 15 volts when its turned fully right instead of 25 volts. The left hand output gives out a full 25 volts.
Also when the selector switch is then changed to amps, both channels do not react when turning the potentiometers.
Can anyone point me in the right direction? Thanks.
Did you have the outputs running through a loud? Otherwise the amps needles won't show anything.
With the rest, find the service manual and start checking the voltages at the test points. User/service manuals from this era had very intricate schematics and troubleshooting procedures. You do likely find some test points that are off and go from there.
Hi Pedro,
Not sure what you mean by having the outputs running through loud?
As to the manuals im going through them now, but as i said the needles on volts are showing something, the left channel only shows 15 volts when in the full posistion. Where as the right channel shows 25 volts, which is the full voltage when the potentiometer is turn fully clockwise.
I will go through the manual, but was hoping someone was able to point me in the correct direction on which board to look at directly linked with this issue?
Not sure what you mean by having the outputs running through loud?
As to the manuals im going through them now, but as i said the needles on volts are showing something, the left channel only shows 15 volts when in the full posistion. Where as the right channel shows 25 volts, which is the full voltage when the potentiometer is turn fully clockwise.
I will go through the manual, but was hoping someone was able to point me in the correct direction on which board to look at directly linked with this issue?
he means "load" not loud.
the ammeters show current drawn - no load, no current drawn.
he is absolutely correct about manuals from this time period; best thing you could do right now is download the service manual and follow along.
not familiar enough with this particular model to point to a specific board.
good luck,
mlloyd1
the ammeters show current drawn - no load, no current drawn.
he is absolutely correct about manuals from this time period; best thing you could do right now is download the service manual and follow along.
not familiar enough with this particular model to point to a specific board.
good luck,
mlloyd1
I have two of them, they work great so have had no reason to open up and poke around. But be sure the current limiting knobs are not turned too far ccw or voltage output will be limited. You did not say if you had the supplies loaded or not.
As others mentioned, that was a typo on my part. I meant load. Without a load across the terminal the current needles will ALWAYS show zero, unless something is wrong. This is because an open circuit never carries current.
Next step, did you measure the voltage output on the terminals to see if it matches the needles? This can help us know what is working and what isn't.
Next step, did you measure the voltage output on the terminals to see if it matches the needles? This can help us know what is working and what isn't.
One can always get the service manual...
ArtekManuals | Your one stop shop for out of print test equipment manuals
Their prices are very, very reasonable and the quality of the scans is very good. 300 dpi for text, 600 dpi for schematics as I recall. You pay and get a download link.
If you prefer dead trees (aka paper) manuals, I suggest Manuals Plus: Manuals Plus - Test Equipment Manuals
~Tom
ArtekManuals | Your one stop shop for out of print test equipment manuals
Their prices are very, very reasonable and the quality of the scans is very good. 300 dpi for text, 600 dpi for schematics as I recall. You pay and get a download link.
If you prefer dead trees (aka paper) manuals, I suggest Manuals Plus: Manuals Plus - Test Equipment Manuals
~Tom
Ok thanks all, im going through the manual at the moment, notice there is reference to an r80 potententiometer used to calibrate the voltages.Which can be adjusted but I need an 12R5 50 watt 5% tolerent resistor as a load to do this. Been trying to find one without much luck. But im also going through the manual first to test voltages. Over the next couple of days when I have free time. I will report back.
Use two of these in parallel ( a few options):
http://www.mouser.com/ProductDetail...=sGAEpiMZZMtbXrIkmrvidDSBj3srglJlFa9R93yFmBk=
http://www.mouser.com/ProductDetail...GAEpiMZZMtbXrIkmrvidKzXrWGN%2biMB/J2gFzpQ4hQ=
http://www.mouser.com/ProductDetail...GAEpiMZZMtbXrIkmrvidKzXrWGN%2biMBCl3ZNZl1XVQ=
http://www.mouser.com/ProductDetail...GAEpiMZZMtbXrIkmrvidHSq9dUqRQr4ZTb%2b/GT/OAU=
http://www.mouser.com/ProductDetail...=sGAEpiMZZMtbXrIkmrvidJh6a0dqqTj9giwXb5YLaKk=
http://www.mouser.com/ProductDetail...GAEpiMZZMtbXrIkmrvidDNaDpN5VXc5yaJVXp%2bT8EY=
http://www.mouser.com/ProductDetail/Ohmite/850F25RE/?qs=sGAEpiMZZMtbXrIkmrvidHSq9dUqRQr4Os4wW3HsuEE=
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Well having obtainned a manual and read start up procedure, I still only get 15 volts max on the left channel, and a full 25 volts on right channel. I then followed procedure for checking amps by shorting channel 1 postive to channel 2 negative. Turn on the power supply with switches on amps turned the current knobs and no readings whatsoever?
Well dont know why i didnt open up the unit before but on the board relating to this problem their seems to be two resistors that have only one leg solder to the board. Think someone has been in this unit before. Will have a look at this later, however do not think that will solve my amps issue.
Update, ok I resoldered two components to the master pcb which is the pcb ive been having issues with. I originally thought these were resistors because they have two strips on them however on the schematics they are diodes. Ive taken a new look at them in the light and they dont look like resistors but ive not seen diodes like these before. Anyway the result was the deflection on the meter was now higher. Instead of a maxium of 15 volts out of 25 I got 20 volts, but no amps. Today ive taken all panels off and had a good look and noticed a fuse was blown. Its a buss fast blow fuse marked 250 vols ac3, I replaced this from another Hp 6227 b I have which is my spare parts one. Anyway after using the fuse i had in that one which was a fast blow fuss 250 volts ac2 so not marked exactly the same. When turning the power supply on with the volt knob set to midway the deflection of the meter was strange it deflected off dial, so past 30 volts when the knob was mid way? Any ideas whats going on?
OK time for you to chill out and start helping us help you. You are giving us next to NO information. The way things are going right now, you are going to possibly make things worse, not better. You need to start being more systematic or you are just going to be flailing around mindlessly. Sit down with the instruction manual. If you reference parts, give us part numbers so that we can see what it does in the schematic. If you reference voltages, do it using a multimeter.
You still haven't said if you are putting a resistor across the inputs when checking amperage. If you aren't, that's why you are not seeing anything.
You also haven't said a THING about using a multimeter to check the real output voltage. For the time being, ignore the fact that those needles even exist. There are a variety of things that can go wrong to cause what you see and not all of it is in the power supply itself. So for the time being start giving us values using a multimeter for voltage (do NOT measure amperage without some sort of load/resistor inline or you will blow the fuse in your meter).
Pedro by the way I am chilled out, so dont need to chill. Ok will take your advice, about giving more direct information sorry this is the first time I really tried to do this so need some guidance on whats needed. As to you telling me I need to put load when doing the impedance test, according to the manual thats not the case, its states and I quote in the manual " short the terminal of channel a + with the negative of chanel b and short the termianl of chanel a - with the + positive of chanel b. The only time the manual mentions putting a load resistor on is when calibrating.
Hi im back, ok on some advice from Pedro ive taken another look at my oower supply. Please all forgive me im new to trying to repair test equipment.
I took another look around inside the meter and noticed on the crowbar pcb R8 resistor was only attached by one leg. This resistor is 300 ohm 2watt. So I resoldered it to the board. Switched the supply on, with it set to middle on the volts potentiometer. The meter read infinitive and measuring it with my fluke DMM the voltage reading on the outputs was 50 volts.
I took another look around inside the meter and noticed on the crowbar pcb R8 resistor was only attached by one leg. This resistor is 300 ohm 2watt. So I resoldered it to the board. Switched the supply on, with it set to middle on the volts potentiometer. The meter read infinitive and measuring it with my fluke DMM the voltage reading on the outputs was 50 volts.
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