Advice on DC - DC converter in place of 7805 VR

[Dopy25]

I have read multiple times about replacing the voltage regulator on various systems and have even bought a few of the Traco branded ones, but they aren't cheap. I'm not necessarily looking to skimp but that's kinda what it comes down to.

 

This is the traco branded one I placed into a SMS as well as one other console I can't remember at the time. I know I still have one of these converters somewhere, but I went to look for a few more and realized why I only bought 3.

 

https://www.digikey.com/en/products/detail/traco-power/TSR-1-2450/9383780

 

Retro consoles don't really push the limits, so is it really that important to go with a traco that is supposed to last 100+ years, or would a less expensive alternative do the same? I can't tell much difference in a few of these as far as input/output. The only thing that looks different to me is the part numbers, and a few of them have a higher minimum input but the same output.

 

Can any of you that know more about components fill me in with some advice, please?

 

I am thinking these won't suffice because they have 500ma out

https://www.digikey.com/en/products/detail/xp-power/VR05S05/13147728

 

https://www.digikey.com/en/products/detail/aimtec/AMSRI-7805-NZ/12440114

 

https://www.digikey.com/en/products/detail/cui-inc/VX7805-500/7350283

 

https://www.digikey.com/en/products/detail/aimtec/AMSRB-7805Z/12457789

 

These have 1a out

https://www.digikey.com/en/products/detail/xp-power/VR10S05/13147713

 

https://www.digikey.com/en/products/detail/aimtec/AMSRB1-7805JZ/12440009

 

https://www.digikey.com/en/products/detail/aimtec/AMSRB1-7805Z/12458333

 

https://www.digikey.com/en/products/detail/cui-inc/P78E05-1000/9649654

 

https://www.digikey.com/en/products/detail/xp-power/TR10S05/6707495

 

https://www.digikey.com/en/products/detail/recom-power/R-78E5-0-1-0/4930585

 

 

Also not sure the difference between how some of them say "Linear Regulator Replacement" and some say "Non-Isolated PoL Module"

 

I am looking to purchase multiple for various systems, most recently a turbografx-16 and I don't want to use the wrong part and fry the board. I understand these are not really to be used in most consoles that have multiple regulators, but older stuff that has only one regulator should be fine. I am looking for less strain and lower temperature.

 

Thanks for any help!

[the_crayon_king]

As far as amperage 500ma might be too low for a lot of consoles. I don't know there ramifications of not supplying enough amperage but I can't imagine it would be good.

I would either match or exceed whatever is currently in the console. 

 

Aren't there different filter capacitor requirements when using these ? I see the Traco has built in capacitors. It is just something to be aware of because some of the other ones suggest capacitors and inductors on the inputs. 

I think if I were doing this I might try to order bulk from here: https://www.trcelectronics.com/View/TRACO-Power/TSR 1-2450E.shtml?gclid=CjwKCAjwn6GGBhADEiwAruUcKoiQltBfv8JM1Mb8WJ_NAH33Qp4LVxRBwHS8J6bVaFlcDHzSyfTkmRoCPIEQAvD_BwE

If you order 10 or more it's around 3$ a pop. 

 

As I understand it these are meant to replace 780X linear regulators. Just make sure you get the pin order correct.

 

 

Anyway, my biggest concern when doing this would new noise or exacerbation of existing noise on the video/audio output.

That was the biggest issue I have heard about these regulators was noise; which may be corrected with additional filter capacitors.  

So it may be worth it to keep a few 2A 7805s around for situations where replacement with the TRACO doesn't work out.

 

[Dopy25]

8 minutes ago, the_crayon_king said:

Anyway, my biggest concern when doing this would new noise or exacerbation of existing noise on the video/audio output.

That was the biggest issue I have heard about these regulators was noise; which may be corrected with additional filter capacitors.  

So it may be worth it to keep a few 2A 7805s around for situations where replacement with the TRACO doesn't work out.

That's what I understand as well, but I thought it was in systems that have multiple regulators. I will for sure keep that in mind. I have a couple of 2a 7805's that I got from console5 not long ago so I will remember that.

 

Seems like shipping to my location from TRC is a bit over 12 causing the cost to jump to around $4 each in the long run. Which is roughly the same as what digikey has them for. 

 

Is there any advantage or disadvantage to using TSR 1-2450E over TSR 1-2450?

 

The other thing I notice is that in the TSR 1-2450E it is listed as "Non-Isolated PoL Module" not "Linear Regulator" like in the TSR 1-2450

 

19 minutes ago, the_crayon_king said:

Aren't there different filter capacitor requirements when using these ? I see the Traco has built in capacitors. It is just something to be aware of because some of the other ones suggest capacitors and inductors on the inputs. 

Maybe the built in capacitors is the reason for using the Traco over others but I'm not sure. I'd like to know that part as well.

 

Thanks for the input!

[the_crayon_king]

1 hour ago, Dopy25 said:

That's what I understand as well, but I thought it was in systems that have multiple regulators. I will for sure keep that in mind. I have a couple of 2a 7805's that I got from console5 not long ago so I will remember that.

 

Seems like shipping to my location from TRC is a bit over 12 causing the cost to jump to around $4 each in the long run. Which is roughly the same as what digikey has them for. 

 

Is there any advantage or disadvantage to using TSR 1-2450E over TSR 1-2450?

 

The other thing I notice is that in the TSR 1-2450E it is listed as "Non-Isolated PoL Module" not "Linear Regulator" like in the TSR 1-2450

 

Maybe the built in capacitors is the reason for using the Traco over others but I'm not sure. I'd like to know that part as well.

 

Thanks for the input!

Well they do have different Classes. One is A(TSR-1-2450) one is B (TSR 1-2450E). I think B is residential and A is commercial.

check out the application notes:

https://www.tracopower.com/series/tsr-1

https://www.tracopower.com/series/tsr-1e

 

You can see that both have suggested external filters to meet these classes.

Further the 1-E has 80mv p-p ripple and the TSR-1-2450 has 50mv ripple (lower is better). 

 

TLDR I would go with the TSD-1-2450. The suggested input filter is 2 10uf 50V capacitors and a 5.6uh choke.

 

 

I have seen drop in replacement PCBs that have a switching regulator and then all the additional filter components. Then it breaks out to 3 little L header pins so that it can fit into the 7805 footprint.

I think something like the TPS62912 might be ideal to make something like that with. They are expensive but I might design a PCB around it and see what it can do. 

 

Edited June 15, 2021 by the_crayon_king

[Dopy25]

23 minutes ago, the_crayon_king said:

Well they do have different Classes. One is A(TSR-1-2450) one is B (TSR 1-2450E). I think B is residential and A is commercial.

check out the application notes:

https://www.tracopower.com/series/tsr-1

https://www.tracopower.com/series/tsr-1e

 

You can see that both have suggested external filters to meet these classes.

Further the 1-E has 80mv p-p ripple and the TSR-1-2450 has 50mv ripple (lower is better). 

 

TLDR I would go with the TSD-1-2450. The suggested input filter is 2 10uf 50V capacitors and a 5.6uh choke.

 

 

I have seen drop in replacement PCBs that have a switching regulator and then all the additional filter components. Then it breaks out to 3 little L header pins so that it can fit into the 7805 footprint.

I think something like the TPS62912 might be ideal to make something like that with. They are expensive but I might design a PCB around it and see what it can do. 

 

Did you means TSR-1-2450 or is there another one I should be looking at?

 

I guess I am more lost now than when I started because I know I have used the one here on digikey with no issues. It works great in my SMS. I can't remember the other console I used one it. Maybe a model 2 Genesis. I'd have to look. I know I bought 3 and used 2.

 

I was hoping to get answers on a more cost efficient solution.

I know others here have used these as replacements with no additional components. I'm not sure if all the extra circuitry is necessary for what is essentially a step down converter with built in filtering.

[the_crayon_king]

2 hours ago, Dopy25 said:

Did you means TSR-1-2450 or is there another one I should be looking at?

 

I guess I am more lost now than when I started because I know I have used the one here on digikey with no issues. It works great in my SMS. I can't remember the other console I used one it. Maybe a model 2 Genesis. I'd have to look. I know I bought 3 and used 2.

 

I was hoping to get answers on a more cost efficient solution.

I know others here have used these as replacements with no additional components. I'm not sure if all the extra circuitry is necessary for what is essentially a step down converter with built in filtering.

Yes I meant TSR-1-2450*. For your uses you will probably be fine with that. If you need to add those additional components the two 10uf and the 5.6uh inductor shown in that one link. 

 

For what you are trying to do that is probably going to be the cheapest thing besides making your own little PCB from SMD parts.

Edited June 16, 2021 by the_crayon_king

[+-^CrossBow^-]

I can't recall exactly which ones it was, but one of the last batches of 1-2450 Traco's that I bought ended up causing issues for a few of my clients that I installed them into their 7800s. They DC-DC switchers worked fine, but required an input voltage of +12 to actually kick out +5 regulated. This was fine until the Dragon Fly cartridge came along because the passthrough power on that device only provides a +9. Because of this, it was causing those 1-2450s I was using to only kick out +3 volts and that prevented the 7800 from powering up properly with a DF cart. So the only solution on those was to use two power supplies. One for the 7800 that works with the 1-2450, and another to power the DF cart.

 

As a result, I've only been purchasing the more expensive $12 - $14 2-2450 versions as those provide a 2A output of current and only require a minimum of +7 to work and provide the +5.

 

I've installed a bunch of these into my own consoles with the exception of the Genesis model 1 as it did not seem to like the DC-DC switchers at all. I also ran into a problem installing one of these into a client's SMS where it was causing some graphical glitching on occasion. Specifically columns, Moon Walker, and apparently sometimes with Sagaia as well.

 

So they work great in most consoles but do need to test them and let your consoles burn in a bit before buttoning them up and calling them good just in case.

 

 

[Dopy25]

12 minutes ago, -^CrossBow^- said:

I can't recall exactly which ones it was, but one of the last batches of 1-2450 Traco's that I bought ended up causing issues for a few of my clients that I installed them into their 7800s. They DC-DC switchers worked fine, but required an input voltage of +12 to actually kick out +5 regulated. This was fine until the Dragon Fly cartridge came along because the passthrough power on that device only provides a +9. Because of this, it was causing those 1-2450s I was using to only kick out +3 volts and that prevented the 7800 from powering up properly with a DF cart. So the only solution on those was to use two power supplies. One for the 7800 that works with the 1-2450, and another to power the DF cart.

 

As a result, I've only been purchasing the more expensive $12 - $14 2-2450 versions as those provide a 2A output of current and only require a minimum of +7 to work and provide the +5.

 

I've installed a bunch of these into my own consoles with the exception of the Genesis model 1 as it did not seem to like the DC-DC switchers at all. I also ran into a problem installing one of these into a client's SMS where it was causing some graphical glitching on occasion. Specifically columns, Moon Walker, and apparently sometimes with Sagaia as well.

 

So they work great in most consoles but do need to test them and let your consoles burn in a bit before buttoning them up and calling them good just in case.

 

 

I did notice a few 1-2450s that seemed to be variable and can put out 3.3 but I think I left those out. So basically I'm looking for a less expensive alternative and the reality is I need a more expensive one. Jeez. 

 

I'll be getting a tg16 without an RF shield and that means no heatsink. I was hoping to put in a dc-dc to alleviate the need for a heatsink. This is going to be fun trying to figure out what works best. 

 

Thanks for the info, both of you. I appreciate it. 

 

Thinking about that issue with a few clients needing 12v... Could it be the input wattage causing the drop to 3v? What does the df put out for watts?

Edited June 16, 2021 by Dopy25

[+-^CrossBow^-]

I did install a 1-2450 (2 of them actually) into my TurboDUO but it is using the original PSU for it and that puts out nearly 14v without a load so it is enough to power it all up properly. I do notice some noise on the audio side when using my Everdrive and some HuCards but CD games are fine.

 

[Dopy25]

14 hours ago, -^CrossBow^- said:

I did install a 1-2450 (2 of them actually) into my TurboDUO but it is using the original PSU for it and that puts out nearly 14v without a load so it is enough to power it all up properly. I do notice some noise on the audio side when using my Everdrive and some HuCards but CD games are fine.

 

Ok great. I will only have the TG16 but as I mentioned, no RF or heatsink.

 

I use a 12v 4a switching supply and a step down converter to 10.1v so I am pretty sure it is a steady flow, but I have yet to test if it drops under load.

[Dopy25]

Does anyone know if I can use the L78S05CV from console5 without a heatsink in my tg16? As mentioned before, I don't have an RF shield for it, therefore no heatsink. I was looking at using the dc-dc but I can't find the one I bought before and am not looking forward to buying 1 and waiting.

 

I do have an L78S05CV that I got from console5 awhile back but I'm worried about heat. From what I understand, the documentation says they can use above 2A if adequate heatsink is applied. I'm not sure if that means no heatsink is required below 2A or even if the tg16 pulls more than 2A.

 

If that's not acceptable, how big is the stock heatsink? Could I use a raspberry pi heatsink? Those have double sided tape to attach so I wonder if I should remove that and use thermal paste, with somehow attaching it to the Voltage regulator. 

 

Any help is appreciated.

 

 

Edit: this is what I mean. It also looks like the adhesive is some sort of thermal pad tape. 

 

 

This is what it looks like in place. I faced it up for better air flow and because I have the room.

 

Edited June 18, 2021 by Dopy25

[emerson]

The below links are useful when determining an appropriate heatsink, or if you need one at all.

 

https://www.petervis.com/electronics/Voltage_Regulator_Heatsink/Heatsink_for_TO-220_Voltage_Regulator.html

https://www.petervis.com/electronics/Voltage_Regulator_Heatsink/heat-sink-calculator.html

 

I plugged following values into the calculator. These came from the L78S05CV datasheet and power requirements labelled on the bottom of a TG16 I saw on ebay. It says a heatsink with a thermal resistance of 25.6'C or below is required.

 

Tj = 150

Ta = 27

Vi = 10.5

Vo = 5

I = 0.73

 

According to the calculator results, the heatsinks in this link are sufficient: https://www.mouser.com/Thermal-Management/Heat-Sinks/_/N-5gg0Z1yzvvqx?Rl=5gg0ZerfnZ1yyp1k2Z1yyp1luSGT&Keyword=to220&FS=True&Ns=Pricing|0

 

[Dopy25]

5 hours ago, emerson said:

The below links are useful when determining an appropriate heatsink, or if you need one at all.

 

https://www.petervis.com/electronics/Voltage_Regulator_Heatsink/Heatsink_for_TO-220_Voltage_Regulator.html

https://www.petervis.com/electronics/Voltage_Regulator_Heatsink/heat-sink-calculator.html

 

I plugged following values into the calculator. These came from the L78S05CV datasheet and power requirements labelled on the bottom of a TG16 I saw on ebay. It says a heatsink with a thermal resistance of 25.6'C or below is required.

 

Tj = 150

Ta = 27

Vi = 10.5

Vo = 5

I = 0.73

 

According to the calculator results, the heatsinks in this link are sufficient: https://www.mouser.com/Thermal-Management/Heat-Sinks/_/N-5gg0Z1yzvvqx?Rl=5gg0ZerfnZ1yyp1k2Z1yyp1luSGT&Keyword=to220&FS=True&Ns=Pricing|0

 

Awesome sauce. Thanks for the info!

 

Based on what I see there, the heatsink I have attached should be sufficient, but I think I will drill a hole and add thermal paste instead of using the included thermal adhesive pad.