HM3000 Track Output not quite as expected.

[Ross-353777]

Just returning to the hobby after more than 40 years break. I have a HM3000 from 1980 that’s had about a years use then stored; it was very erratic to begin with, but I now have it stable, after fixing many dry soldered joints. I am not sure if I still have some faults or if these are design issues.

I wonder if someone who has a HM3000 that could just observe the ‘Track Power’ LED brilliance. With Variable Momentum:Off, Auto-Power Regulator:On set for Max, Local Power, Forward Direction, Brake:Min. When moving the regulator slowly from 1 through to 12 does the LED just continue to get brighter? With mine I am seeing a dip at around regulator position 6, also observable with a voltmeter.

In the 11th edition catalogue it states the regulator goes “from full on to full off”. When the regulator is in position 1 minimum (or position 2) (no momentum, no APR, Forward Direction) it reads 1.8volts, is this normal?

I know old kit, just wondered if someone could help.

[P-Henny]

Ross,

Be aware that HM3000 has got nothing to do with HM DC which is a Bluetooth APP controlled system. You may find that your thread is moved by a mod to the 'General Discussion' forum which is the correct forum for these ancient DC Analogue systems.

Not really your fault as the forum indexing titles lacks clarity. The text description at the top of the HM DC index page does state however that the HM DC forum is for HM6000 series products.

[Ross-353777]

Thanks Paul, a lot has changed in 40 years... :-)

Still hoping someone has a HM3000 that can help

[Ross-353777]

Ok, I have now worked it out. The controller needed a load. Tested with a motor connected with APR and the track output voltage steadily rises - no dips. Also without APR the minimum voltage with a motor connected went down to 0.4v.

I have just one problem with it now, and that's a resistor R6 gets very hot, its blackened the PCB, not quite sure what the purpose of it is. I have uprated it to a higher wattage. Its located above the Overload LED, and heats the case up significantly. Just in case anyone should read this and has one that also does this, please let me know.

Other than that it seems ready for operating.