Heathkit IP - 12 Battery Eliminator Power Supply, Housing Repainted, TESTED/WORKS
Item History & Price
| Reference Number: Avaluer:51322378 | Bundle Listing: No |
| Model: IP-12 | MPN: IP-12 |
| Country/Region of Manufacture: United States | Brand: Heathkit |
| UPC: Does not apply |
Heathkit IP-12 Battery Eliminator and Power Supply. Thoroughly tested--see the checklist below. Housing repainted. Front panel original. Clean inside. Housing with several markings by previous owner, some of which are not perfectly covered by the new coat of paint (see last photo). Front panel slightly warped at upper left corner (see the last but one photo). Some spots, scratches, and blemishes to front panel. A 2-page print-out from the manual providing specifications, an introd...uction, the circuit description, and the schematic is included.
Heathkit Battery Eliminator/PowerSupply IP-12Maintenance and Repair Checklist
Type of rectifier used (metallic or what looks like silicon)*: silicon (I assume; please see photo)All three capacitors--capacitance and leak current withinspecs (tested with Sencore LC53): yesSwitch contacts treated with Deox: doneSigns of corrosion/rust inside the unit (none, hardly any, some, much): noneAll terminal posts are fixed/not loose: finePower cord safe; no worn spots, especially where it entershousing: repaired with a new grommet and cable reinforcement (see pic).On/off switch works reliably: yes6V/12V Range Switch works reliably: yesVoltage Control Switch (0-6V; 0-12V) works reliably: yes, but it will jump to zero at the very extreme clockwise setting.Test-run for 3 hours with 2.5 Ohm load at 12.5V (5 amp) atfiltered terminals—no problems: fineBoth Voltmeter and Ampmeter work and do not stick: fineBoth Voltmeter and Ampmeter can be nulled: yesNo erratic meter movements during testing: noneMax. voltage** with 2 Ohm load at 6V Range Switch setting: 12VMax. voltage** with 2 Ohm load at 12V Range Switch setting: 17VRipple measured with oscilloscope with a 2.0 Ohmload at 12V (12V Range setting): abt. 20mV (.2%)Ripple measured with oscilloscope with a 25 Ohmload at 12V (12V Range setting): abt. 2mV (.02%)Date(s) tested: 2/16/2021 *Note 1: The type of rectifier employed in IP-12 units changed over time. My IP-12Manual described it as containing “magnesium copper sulfide diodes, ” the stack of which Iassume looks like a selenium rectifier, with large parallel cooling plates.Other (probably later) IP-12 models, like the one in this auction, contain what I assume to be silicon diodes. For a description of metallic rectifiers, including a comparison of selenium and magnesium copper sulfide types, see Theodore Conti, Metallic Rectifiers and Crystal Diodes, J.F. Rider Publ., 1958 (can be found online via Google). **Note 2: The maximum voltage depends on the current draw of the load. Even with a 5A load, the maximum voltage (Voltage Control Switch turned far clockwise) exceeds the selected voltage. To avoid damage to the voltmeter and capacitors, I recommend rotating the Voltage Control Switch all the way counterclockwise before powering up the unit for the first time and staying within the selected voltage range.
Heathkit Battery Eliminator/PowerSupply IP-12Maintenance and Repair Checklist
Type of rectifier used (metallic or what looks like silicon)*: silicon (I assume; please see photo)All three capacitors--capacitance and leak current withinspecs (tested with Sencore LC53): yesSwitch contacts treated with Deox: doneSigns of corrosion/rust inside the unit (none, hardly any, some, much): noneAll terminal posts are fixed/not loose: finePower cord safe; no worn spots, especially where it entershousing: repaired with a new grommet and cable reinforcement (see pic).On/off switch works reliably: yes6V/12V Range Switch works reliably: yesVoltage Control Switch (0-6V; 0-12V) works reliably: yes, but it will jump to zero at the very extreme clockwise setting.Test-run for 3 hours with 2.5 Ohm load at 12.5V (5 amp) atfiltered terminals—no problems: fineBoth Voltmeter and Ampmeter work and do not stick: fineBoth Voltmeter and Ampmeter can be nulled: yesNo erratic meter movements during testing: noneMax. voltage** with 2 Ohm load at 6V Range Switch setting: 12VMax. voltage** with 2 Ohm load at 12V Range Switch setting: 17VRipple measured with oscilloscope with a 2.0 Ohmload at 12V (12V Range setting): abt. 20mV (.2%)Ripple measured with oscilloscope with a 25 Ohmload at 12V (12V Range setting): abt. 2mV (.02%)Date(s) tested: 2/16/2021 *Note 1: The type of rectifier employed in IP-12 units changed over time. My IP-12Manual described it as containing “magnesium copper sulfide diodes, ” the stack of which Iassume looks like a selenium rectifier, with large parallel cooling plates.Other (probably later) IP-12 models, like the one in this auction, contain what I assume to be silicon diodes. For a description of metallic rectifiers, including a comparison of selenium and magnesium copper sulfide types, see Theodore Conti, Metallic Rectifiers and Crystal Diodes, J.F. Rider Publ., 1958 (can be found online via Google). **Note 2: The maximum voltage depends on the current draw of the load. Even with a 5A load, the maximum voltage (Voltage Control Switch turned far clockwise) exceeds the selected voltage. To avoid damage to the voltmeter and capacitors, I recommend rotating the Voltage Control Switch all the way counterclockwise before powering up the unit for the first time and staying within the selected voltage range.
