AC output?

[toddtmw]

So, I went through all of my Atari AC output adapters and checked the voltage. All of the "9" volt adapters are between 9.8 and 10.1 volts.

 

Interestingly, the "9.5" volt adapter that came with the 1027 printer was like 9.01 volts.

 

Is there any danger of these adapters hurting a disk drive, computer or other device with these higher than specified voltages?

 

Do any of these adapters cause failure like the 5-volt 800xl ingot adapters can?

 

Thanks for the info!

[+DrVenkman]

So, I went through all of my Atari AC output adapters and checked the voltage. All of the "9" volt adapters are between 9.8 and 10.1 volts.

 

Interestingly, the "9.5" volt adapter that came with the 1027 printer was like 9.01 volts.

 

Is there any danger of these adapters hurting a disk drive, computer or other device with these higher than specified voltages?

 

Do any of these adapters cause failure like the 5-volt 800xl ingot adapters can?

 

Thanks for the info!

 

Mine all tested about the same; these are simple unregulated transformers; they will read higher than nominal without a current load on them.

 

As for failure modes, I don't really know. Every single one of my mine seem to be fine after 34 - 35 years.

[Bryan]

Yeah, transformers are a little different. They're designed to give an RMS voltage at a specific load but will measure higher or lower at other loads. Because the AC voltage must be rectified and regulated inside the device itself, there's a lot of tolerance there.

[Rybags]

Yep, I think it comes down to what the voltage regulators can handle. Fairly sure the 1050 has the +5 and +12 regulation before anything else gets powered. And failure mode of voltage regs - don't they just blow and go open-circuit?

[+DrVenkman]

And failure mode of voltage regs - don't they just blow and go open-circuit?

In 2600’s, from personal experience, old 7805’s can heat up and suffer voltage drops.

[Bryan]

Yep, I think it comes down to what the voltage regulators can handle. Fairly sure the 1050 has the +5 and +12 regulation before anything else gets powered. And failure mode of voltage regs - don't they just blow and go open-circuit?

Thousands of ingot supplies disagree.

[1050]

Failure mode of the ingots is to short full rectified power

thru the regulator - same 7805, it just can't keep it's

cool as well. Issue is probably the epoxy has pulled

away from the mounting tab on the 7805 and it no

longer is in contact with the epoxy for use as a

heat sink.

 

7805 and 7812 are now available in chineseium on

ebay as switching devices. They seem to work good,

but have no mounting heat sink tab. They will require

desoldering of the legs to turn them around for decent

mounting in a 1050 drive for example since the circuit

board is right up against the aluminum heat sink and

might short to it over time.

 

http://www.ebay.com/itm/1A-6-5-40V-to-5V-DC-DC-Converter-Buck-Module-replace-TO-220-L7805-LM7805-LDO-IC/272451377177

http://www.ebay.com/itm/14-40V-24V-to-12V-Voltage-Regulator-DC-DC-Converter-Step-Down-Buck-Module-L7812/272451394766

 

When you order three, they will come as three on a single

board. You will have to work them to snap them apart.

Impossible to see the slice they do to the board but it's

there and they do just come apart like magic.

[BillC]

In 2600’s, from personal experience, old 7805’s can heat up and suffer voltage drops.

I think that's a thermal protection mode, reducing power output to prevent failure from overheating.

 

It is normally caused by poor thermal contact to the heatsink or inadequate heatsink/airflow.

 

In this case most likely the first, caused by old thermal compound that needs to be replaced.

Edited August 10, 2017 by BillC