Electronics > Repair

HP 6114A Newbie Repair

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TimFox:
In this type of power supply, the decade switches to program the output voltage form a variable resistor, as part of the DC feedback circuit.
Each resistor has a corresponding switch element that shorts it out, or not.
If a contact somewhere in the switch is dirty, when that contact is supposed to close (0 \$\Omega\$ for that part of the resistor string), the resulting resistance will be too high for the setting, and the output voltage (proportional to the total resistance of the string) will be too high.
Therefore, it is important to clean the switch contacts.

AlpineJoe:

--- Quote from: coppercone2 on November 23, 2024, 10:41:53 pm ---you can try  :-//


https://www.heisener.com/ProductDetail/Y000715K8200V0L

good luck

https://www.integrated-circuit.com/products-detail/Y000715K8200V0L/EIS-2897594.html


https://www.digikey.com/en/products/detail/stackpole-electronics-inc/RNCF1206TKW15K8/16206097

--- End quote ---
Here's an interesting source.  Was recommended this place from the HP test instrument Groups.io page.
https://www.texascomponents.com/store/VishayFoilResistors.asp

Looks like they can make custom resistors quickly.  Not sure the cost but the author didn't think it was exhorbitant. 


HOLY SMOKES! They will make a custom resistor for about $13.
https://webdirect.texascomponents.com/ProductDetails.asp?ProductCode=VSMP%5F1206%5FCUSTOM%5F0%2E01
0.3W  0.2ppm  0.01%  (Any Custom Value from 250 to 25K ohms @ 0.01%)

or 1/2W for $16.23
https://webdirect.texascomponents.com/ProductDetails.asp?ProductCode=VSMP%5F2010%5FCUSTOM%5F0%2E01 VSMP 2010 Bulk Metal (Z) Foil Surface Mount Resistor; (aka Y1627) 0.5 W; 0.2 ppm/C TCR  0.01%

Amazing!

AlpineJoe:

--- Quote from: AlpineJoe on November 24, 2024, 06:46:09 am ---
Here's an interesting source.  Was recommended this place from the HP test instrument Groups.io page.
https://www.texascomponents.com/store/VishayFoilResistors.asp

Looks like they can make custom resistors quickly.  Not sure the cost but the author didn't think it was exhorbitant. 


HOLY SMOKES! They will make a custom resistor for about $13.
https://webdirect.texascomponents.com/ProductDetails.asp?ProductCode=VSMP%5F1206%5FCUSTOM%5F0%2E01
0.3W  0.2ppm  0.01%  (Any Custom Value from 250 to 25K ohms @ 0.01%)

--- End quote ---

Unfortunately 'no minimum order' and the fact the form shows I can order 1 pc doesn't mean I can order only 1 pc.

I contacted TCC asking what the price with shipping would be and their reply was "The MOQ for the series is 5 pc. since is a very peculiar R value."
Not sure why my 'any custom value from 250 to 25K' is special.

Meanwhile I can find 5ppm parts of 15K and 820 ohm resistors in stock from Digikey for <$5 shipped, and really I just need to be in the range that A2R5 can adjust for so I could just use a single close value vs hitting 15.82K exactly.

coppercone2:

--- Quote from: AlpineJoe on November 24, 2024, 06:46:09 am ---
--- Quote from: coppercone2 on November 23, 2024, 10:41:53 pm ---you can try  :-//


https://www.heisener.com/ProductDetail/Y000715K8200V0L

good luck

https://www.integrated-circuit.com/products-detail/Y000715K8200V0L/EIS-2897594.html


https://www.digikey.com/en/products/detail/stackpole-electronics-inc/RNCF1206TKW15K8/16206097

--- End quote ---
Here's an interesting source.  Was recommended this place from the HP test instrument Groups.io page.
https://www.texascomponents.com/store/VishayFoilResistors.asp

Looks like they can make custom resistors quickly.  Not sure the cost but the author didn't think it was exhorbitant. 


HOLY SMOKES! They will make a custom resistor for about $13.
https://webdirect.texascomponents.com/ProductDetails.asp?ProductCode=VSMP%5F1206%5FCUSTOM%5F0%2E01
0.3W  0.2ppm  0.01%  (Any Custom Value from 250 to 25K ohms @ 0.01%)

or 1/2W for $16.23
https://webdirect.texascomponents.com/ProductDetails.asp?ProductCode=VSMP%5F2010%5FCUSTOM%5F0%2E01 VSMP 2010 Bulk Metal (Z) Foil Surface Mount Resistor; (aka Y1627) 0.5 W; 0.2 ppm/C TCR  0.01%

Amazing!

--- End quote ---

i think its cheaper lasers that make this possible

At some level, a tiny metal paper is just being passed through a laser printer


but it does not have leads on it. I guess you need a litle pCB with some thick copper leads

factory:
They do through hole parts for a little more $ too.

https://webdirect.texascomponents.com/ProductDetails.asp?ProductCode=Z201%5FCustom%5F0%2E10

David

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