Old style power cable needed

[jeffjmr]

I need to replace my power cable on my Heath TT-1.

It is an IEC 30620 C1. I can find notebook power supply cables that are functional equivalents but they are all too short. There do not appear to be any C1 connectors available anywhere to assemble one either.

Any ideas?

Thanks,
Jeff

[PaulAm]

If you go to the hp -agilent-keysignt-equipment group and search for the topic "Current source for old oval HP power cords", one member has submitted an stl file to pring a compatible housing using some standard crimp pins.

Actually, you don't even have to do that, it's on thingiverse: https://www.thingiverse.com/thing:4862134

[mr.fabe]

How about this one with the ground pin?

https://www.ebay.com/itm/174952307919?epid=19031315127&hash=item28bbf85ccf:g:8RsAAOSwf4hggfYR

If not, you may want to follow what others have done with their TT-1's and modify the IEC connector to C8 type or the C14 type.

[andy3055]

Can you post a picture of the receptacle? If my guess is correct, you may be able to use a C7 instead of C1.

Most probably this one: https://www.ebay.com/itm/324737207087?hash=item4b9bd88b2f:g:c1IAAOSw~ZRhB-GF

[jeffjmr]

Can you post a picture of the receptacle? If my guess is correct, you may be able to use a C7 instead of C1.

Most probably this one: https://www.ebay.com/itm/324737207087?hash=item4b9bd88b2f:g:c1IAAOSw~ZRhB-GF

Bingo!

I had already confirmed I could use a C7, but had not found one longer than 18”. That 3 footer will work perfectly.

Just have to decide now the pros and cons to converting to C14, specifically how grounding the chassis of the TT-1 might affect safety or performance.

Thanks!
Jeff

[andy3055]

C1 is a 2 conductor cable with no ground. so what is the deal with the grounding you have mentioned?

[jeffjmr]

C1 is a 2 conductor cable with no ground. so what is the deal with the grounding you have mentioned?

No issue if I stick with C1 but some TT-1 owners convert to C14. I am assuming they hookup the ground lead but I guess maybe they just use the live and neutral and use the C14 for polarity. I would like to find out and know what affect hooking up the ground lead to the chassis might have.

Jeff

[BrokenYugo]

I can't see how grounding it would do anything but improve safety, any Y cap leakage would be shunted to earth, but that shouldn't be any issue.

[jeffjmr]

I’m in the US, so connecting the ground to the chassis will introduce the neutral to the chassis resulting in mains power potential between the live and chassis. As built the chassis is insulated from the neutral line.

If my analysis is faulty someone please correct me.

Jeff

[jpwolfe31]

If the instrument fails and the mains shorts to the enclosure, and the enclosure is grounded (or neutral) the fuse will blow or the breaker will trip.  If the same happens without ground, the mains voltage is on the enclosure and if you touch it, you may be the path to ground.

[mansaxel]

Defeating a ground for an appliance is a very serious problem. The device has been designed with things like isolation distances and insulating layers based on the assumption that exposed conductive chassis will be grounded.

An ungrounded appliance will have another design, with more insulation and no exposed metalwork.

That horrible NEMA connector is best replaced by a "Mickey Mouse" connector, the IEC C5/C6 combination:



It fits reasonably well, with small modifications, in the NEMA cutout.

[tooki]

Defeating a ground for an appliance is a very serious problem. The device has been designed with things like isolation distances and insulating layers based on the assumption that exposed conductive chassis will be grounded.

An ungrounded appliance will have another design, with more insulation and no exposed metalwork.

Oh, sweet summer child. You forget that not everything was build recently, with modern safety standards.

The device in question is an old device originally built without a ground (so no ground to defeat). It’s also a metal chassis. It used to be very common to have exposed metalwork, or even live chassis.

The question being asked is whether adding a ground to this device introduces any new hazards.


P.S. It’s a common misconception that exposed metalwork requires grounding, even in modern devices. It does not. You can go to any electronics store and buy things like DVD players, stereos, TVs and toasters that have metal housings and are mains powered without a grounded cord.

[mansaxel]

Defeating a ground for an appliance is a very serious problem. The device has been designed with things like isolation distances and insulating layers based on the assumption that exposed conductive chassis will be grounded.

An ungrounded appliance will have another design, with more insulation and no exposed metalwork.

Oh, sweet summer child. You forget that not everything was build recently, with modern safety standards.

The device in question is an old device originally built without a ground (so no ground to defeat). It’s also a metal chassis. It used to be very common to have exposed metalwork, or even live chassis.

The question being asked is whether adding a ground to this device introduces any new hazards.


P.S. It’s a common misconception that exposed metalwork requires grounding, even in modern devices. It does not. You can go to any electronics store and buy things like DVD players, stereos, TVs and toasters that have metal housings and are mains powered without a grounded cord.

OK. Understood. I got the original question wrong. No, adding a ground should not be a problem.

The devices with exposed metal chassis but 2-pole mains will be double insulated which probably is not the case with the old device.

[CaptDon]

Some of the older electric typewriters used those cords. Look around second hand stores!!
One local store here has a bin with nothing but used power cords left over from dead donated
appliances. I still see the cords you are looking for from time to time. It is a bit late in the year
for the amateur radio hamfests, but you may find cords there also!!

[factory]

Can you post a picture of the receptacle? If my guess is correct, you may be able to use a C7 instead of C1.

Most probably this one: https://www.ebay.com/itm/324737207087?hash=item4b9bd88b2f:g:c1IAAOSw~ZRhB-GF

Bingo!

I had already confirmed I could use a C7, but had not found one longer than 18”. That 3 footer will work perfectly.

Just have to decide now the pros and cons to converting to C14, specifically how grounding the chassis of the TT-1 might affect safety or performance.

Thanks!
Jeff

Can't understand why you didn't post a picture of the two pin connector in question and add some measurements of the pin spacing/diameter etc.
Note: modern IEC C1 & C7 connectors do not have the same pin spacing.

David