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I recently acquired a HP6209B, and already have the same manual as the one here in the files section, but it does not include the component layout, as it seems that page was left out during the scan. If someone might have a HP6209B paper manual, could they please take a clear hi-res picture of the parts location page and email or post it to the files section? I think the 6207B is almost identical so a picture of that component layout might also be helpful, if it has better resolution as the one present on the 07B 1970 manual I already have that looks very dark, lo-res and low-contrast, so not very usable at all.

The power supply seems to work just fine, other than on the 12mA scale the meter needle pegs all the way to the left beyond zero, even without a load connected. Guessing probably some resistor value has drifted, so a parts layout might be helpful to have. The 120mA scale seems to work fine after calibrating it (it was reading a bit low). And if I put a 10mA load while on the 120mA scale, and then switch to the 12mA scale it will read around 8mA, even after the calibration. About a second after disconnecting the load the needle will start to move left. Volt scales where reading 5V high, but after a meter zero and calibration they are now reading reasonably ok for an analog meter.

One other issue is that the current 10T pot seems a bit stiffer to turn than expected, but is still fully functional. On the other hand the volts 10T 100K pot was replaced with a 50K unit, and the tech even left a note about this inside the power supply taped on top of the main transformer, dated November 1981. The volts adjustment turns with normal feel, and also seems to work fine with this half value pot.

Thanks in advance.

Thank you for the information, that saved me some ghost hunting for drifted resistors in the meter circuit.

Both the voltage and current adjustment pots are Bourns series 3540 which are rated at 2W.


Voltage Adj: 3540S-419-503 (50K)
There is also another part number on them, which seems to be Tektronix related:
311-0946-00: "Tektronix Test Equipment Potentiometer Precision 10 Turn 50K 5% Lin = .05%, Bourns Part # 3540S-419-503".

Current Adj: 3540S-504-203 (20K)
And also has: 3100-18S7 but search did not lead to anything related.

The replaced 50K voltage adjustment pot has a very thin (about 1/8") shaft, and the current adjustment one has a regular 1/4" shaft. Both have identical looking grey knobs with a black inset despite the different shaft diameters. After comparing them with online pictures of the power supply they are definitively different from the original ones, and only the black meter select switch knob seems to match. Taking another look at those two knobs, they definitively look very Tektronix like and this makes me think that the tech that serviced the power supply might have had access to Tek parts, and chose the 50K and corresponding knob just to make do, and even replaced the knob on the current adjust to match.

Was thinking that will now need to ideally find the equivalent 100K Bourns 3540S-419-104 (if that is an actual existing valid number) with the same 1/8" shaft to match the existing knob. But can't seem to get anything on that PN, neither does searching for 3540S-504-104. Instead all I am finding is 3540S-1-104 which is also 100K with the same linearity specs but with a 1/4" shaft. It does come up at Mouser as Obsolete, but they suggest the alternate 3540S-1-104L ROHS part instead for $34. Ebay also has a couple of options at around $20-$25.

Seems like not going to find anything with a 1/8" shaft, so by any chance does anybody have a pair of the correct original matching black HP 1/4 inch shaft knobs?

Correction to my previous post: meant to say MINIMUM OUTPUT VOLTAGE after adding the 47K resistor in series with R10 is about 160V, maximum output is still about 320V.

I am checking some voltages around the current meter circuit: the -3V shown on the schematic to be present at one side of R38/R53 measures only -2.29V. Same value at the cathode of CR8 in the bias supply where this voltage originates. Cathode of CR7 has +1.77V.

CR7 is a 1N4830 "stabistor" 2.4V @ 100mA. Guessing some sort of reference voltage or early zener diode. On the other hand CR8 is listed as 1N3828 and seems to be a regular silicon small signal diode. The way they are connected in series in the bias supply (for among others temperature stability) I would expect the -3V output to be the sum of the CR7 voltage, plus about 0.6-0.7V additional drop of CR8, so indeed about 3V. But in real life CR8 seems to have a drop of only 0.5V as measured, so do I have a bad CR7 that has gone low from the original 2.4V to only 1.77V?

The other bias supply voltages: +43V is at +37.5V, and the +16V is correct at +15.98V.

And at the reference regulator, the +6.2V (33) measures 6.43V, the +12.4V (37) measures 12.66V, and the -6.2V (31) measures -6.22V.

All voltage readings referenced to +S (same as positive/red output binding post with correct rear jumpers in place).
All other rear jumpers where also verified earlier to be in the standard configuration as shown on the schematic.