Polarity for DC in

HoutHans · 09-23-2022, 05:17 AM

Dear Fellow Pentaxians,

I'm currently using a full spectrum modded K-5 for astrophotography and I would like to use the external 8.3 V DC in connector. I have already located the right plug, but now I would like to confirm the polarity. Does anyone out there have a scheme or drawing? I came across this annotated image, but given that getting the polarity right is rather important to avoid frying stuff on the inside, I'd like to double check.

Many thanks in advance.

All the best,
Hans

jgnfld · 09-23-2022, 06:26 AM - **2 Likes**

Originally posted by HoutHans

Dear Fellow Pentaxians,

I'm currently using a full spectrum modded K-5 for astrophotography and I would like to use the external 8.3 V DC in connector. I have already located the right plug, but now I would like to confirm the polarity. Does anyone out there have a scheme or drawing? I came across this annotated image, but given that getting the polarity right is rather important to avoid frying stuff on the inside, I'd like to double check.

Many thanks in advance.

All the best,
Hans

I don't know...reversing the polarity is the most sure-fire way to fix most anything in a sci-fi movie that cannot be fixed with a sufficiently large bomb. I've never seen any gear come to harm from doing so on any show yet! Surely Hollywood/Vancouver wouldn't lie to us would they???!!!

**Bob 256** · 09-23-2022, 08:30 AM

Contrary to any Sci-Fi show, reverse polarity has permanently disabled more equipment than most any other failures. A great way to destroy the enemy's death ray but not recommended for today's electronic equipment.

Take a look here (post #18) - it appears that the center pin is positive in the recommended AC adapter. New AC Adapter for K-5, II, IIs, & K-3... - Page 2 - PentaxForums.com

This has become the de facto standard but there are exceptions out there in case you need to send the enemy a Trojan horse

.

Not a Number · 09-23-2022, 11:34 AM

That should be using the rectangular Hirose connector as I recall. From the bottom plate of my D-AC50:

**Bob 256** · 09-23-2022, 07:59 PM

In searching around, I've found 3 different connector styles shown for the K-5 - the two above and this one which could be a different depiction of the one Not A Number provided. Confusing, but hope one of these applies to your K-5.

Not a Number · 09-23-2022, 08:47 PM - **1 Like**

It's the same Hirose connect used on the majority of the K DSLRs. The ones that don't have a connector and use the dummy battery adapter use the Hirose connector on the adapter. I think the K100D uses a circular coax power connector.

The difference from the diagrams above is my diagram shows the connector and the shroud while the second diagram is a close-up

Crop of my earlier photo (taken with phone so movement blur):

https://www.digikey.com/en/products/detail/hirose-electric-co-ltd/MQ172-3SA-CV-30/5994715

The original blog that identified the connector (sadly the photos are missing) is here:
https://roamingdrone.wordpress.com/2008/09/26/diy-ac-adaptor-for-the-pentax-k10d/

Quote:

Step 6: Wire Hirose connector. Note that the GND is the top-most pin when the plug is inserted into the camera, the +8.3V is the bottom most pin when plugged in. Center pin is unused. Use extreme caution, these plugs are easy to damage when soldering. You may have to strip part of the cable’s coating and replace it with heat-shrink to fit into the stress-relief end of the housing.

HoutHans · 09-23-2022, 11:05 PM

Many thanks for this. I'll see whether there's a way to ascertain polarity within the camera. Fun stuff and I'll keep you posted!

Not a Number · 09-24-2022, 12:58 AM

If you look at the manufacturer's spec sheet for the socket, pin 3 is ground (-), the same as on the plug. This corresponds with the diagram on the D-AC50. If you orient the socket as it is in the K10D with the flat side of the socket facing the rear of the camera pin 3 is towards the top of the camera. This agrees with the blog post.

https://www.digikey.com/en/products/detail/hirose-electric-co-ltd/MQ172-3PA-33/5994729

See drawing 1 for pin numbering

In the picture above, pin 3 is on the right which would be to the top of the K10D.

HoutHans · 10-06-2022, 06:26 AM

I can confirm that this is the correct polarity. With the flat side of the plug facing me (i.e. the way the connector would be inserted in the camera), the top most connector is the - / ground and the bottom one is the plus. Works like a charm now, so many thanks to everyone who chimed in! The plug is indeed fiddly to solder, but it worked.

09-23-2022, 08:30 AM	#3
Bob 256 Site Supporter Join Date: Jun 2008 Location: Idaho Photos: Gallery Posts: 2,378	Contrary to any Sci-Fi show, reverse polarity has permanently disabled more equipment than most any other failures. A great way to destroy the enemy's death ray but not recommended for today's electronic equipment. Take a look here (post #18) - it appears that the center pin is positive in the recommended AC adapter. New AC Adapter for K-5, II, IIs, & K-3... - Page 2 - PentaxForums.com This has become the de facto standard but there are exceptions out there in case you need to send the enemy a Trojan horse.

09-23-2022, 07:59 PM	#5
Bob 256 Site Supporter Join Date: Jun 2008 Location: Idaho Photos: Gallery Posts: 2,378	In searching around, I've found 3 different connector styles shown for the K-5 - the two above and this one which could be a different depiction of the one Not A Number provided. Confusing, but hope one of these applies to your K-5. Attached Images

09-23-2022, 08:47 PM - 1 Like	#6
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	It's the same Hirose connect used on the majority of the K DSLRs. The ones that don't have a connector and use the dummy battery adapter use the Hirose connector on the adapter. I think the K100D uses a circular coax power connector. The difference from the diagrams above is my diagram shows the connector and the shroud while the second diagram is a close-up Crop of my earlier photo (taken with phone so movement blur): https://www.digikey.com/en/products/detail/hirose-electric-co-ltd/MQ172-3SA-CV-30/5994715 The original blog that identified the connector (sadly the photos are missing) is here: https://roamingdrone.wordpress.com/2008/09/26/diy-ac-adaptor-for-the-pentax-k10d/ Quote: Step 6: Wire Hirose connector. Note that the GND is the top-most pin when the plug is inserted into the camera, the +8.3V is the bottom most pin when plugged in. Center pin is unused. Use extreme caution, these plugs are easy to damage when soldering. You may have to strip part of the cable’s coating and replace it with heat-shrink to fit into the stress-relief end of the housing. Last edited by Not a Number; 09-23-2022 at 08:58 PM.

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09-23-2022, 05:17 AM	#1
HoutHans Pentaxian Join Date: Aug 2016 Location: Appingedam Photos: Gallery Posts: 3,123	Polarity for DC in Dear Fellow Pentaxians, I'm currently using a full spectrum modded K-5 for astrophotography and I would like to use the external 8.3 V DC in connector. I have already located the right plug, but now I would like to confirm the polarity. Does anyone out there have a scheme or drawing? I came across this annotated image, but given that getting the polarity right is rather important to avoid frying stuff on the inside, I'd like to double check. Many thanks in advance. All the best, Hans

09-23-2022, 06:26 AM - 2 Likes	#2
jgnfld Moderator Loyal Site Supporter Join Date: Feb 2015 Location: Avalon Peninsula, Newfoundland Photos: Gallery \| Albums Posts: 1,798	Originally posted by HoutHans Dear Fellow Pentaxians, I'm currently using a full spectrum modded K-5 for astrophotography and I would like to use the external 8.3 V DC in connector. I have already located the right plug, but now I would like to confirm the polarity. Does anyone out there have a scheme or drawing? I came across this annotated image, but given that getting the polarity right is rather important to avoid frying stuff on the inside, I'd like to double check. Many thanks in advance. All the best, Hans I don't know...reversing the polarity is the most sure-fire way to fix most anything in a sci-fi movie that cannot be fixed with a sufficiently large bomb. I've never seen any gear come to harm from doing so on any show yet! Surely Hollywood/Vancouver wouldn't lie to us would they???!!!

09-23-2022, 11:34 AM	#4
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	That should be using the rectangular Hirose connector as I recall. From the bottom plate of my D-AC50:

09-23-2022, 11:05 PM	#7
HoutHans Pentaxian Join Date: Aug 2016 Location: Appingedam Photos: Gallery Posts: 3,123 Original Poster	Many thanks for this. I'll see whether there's a way to ascertain polarity within the camera. Fun stuff and I'll keep you posted!

09-24-2022, 12:58 AM	#8
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	If you look at the manufacturer's spec sheet for the socket, pin 3 is ground (-), the same as on the plug. This corresponds with the diagram on the D-AC50. If you orient the socket as it is in the K10D with the flat side of the socket facing the rear of the camera pin 3 is towards the top of the camera. This agrees with the blog post. https://www.digikey.com/en/products/detail/hirose-electric-co-ltd/MQ172-3PA-33/5994729 See drawing 1 for pin numbering In the picture above, pin 3 is on the right which would be to the top of the K10D.

10-06-2022, 06:26 AM	#9
HoutHans Pentaxian Join Date: Aug 2016 Location: Appingedam Photos: Gallery Posts: 3,123 Original Poster	I can confirm that this is the correct polarity. With the flat side of the plug facing me (i.e. the way the connector would be inserted in the camera), the top most connector is the - / ground and the bottom one is the plus. Works like a charm now, so many thanks to everyone who chimed in! The plug is indeed fiddly to solder, but it worked.