Re: Step-down Transformer, AVR thread (and Variac)

Joey,
The wires don't normally come off their solder. A possible overheating is happening during loaded operation or the voltage source is under powered. Please try to show an overhead shot of the circuit layout so we can acertain the voltage (ac) input and the dc output connections before you attempt to solder back.

Re: Step-down Transformer, AVR thread (and Variac)

Joey,
The wires don't normally come off their solder. A possible overheating is happening during loaded operation or the voltage source is under powered. Please try to show an overhead shot of the circuit layout so we can acertain the voltage (ac) input and the dc output connections before you attempt to solder back.

Thank you for the input, Willy. You just stopped me from doing a "bahala na si Batman".

I suspect it came off because of mechanical vibration. The AVR was vibrating more with the C12RSH plugged in, compared to when I'm using the router (with soft start) or the 7.25-inch circular saw.

Also its unlikely that it overheated since that board contains only the power-on delay circuit. The main components are the relay and the Hitachi HA17555 timer IC.

The point where I plan to solder is the ground, because the GND pin of the timer IC is connected to it. Without that wire all that's connected to that net are:
- HA17555's GND pin
- left pin of R3
- left pin of C2
- left pin of Q1
- GND pin of the red/green LED
- wire that goes to the "quick start" button, which when pressed shorts some pins of HA17555 to GND

The disconnected black wire goes to the other board (I dunno how to call it), where the AC to DC conversion happens. Its the black one on the upper left:

Flipping the board over. The wire is connected to the bottom pin of R6.

In summary, I believe the power-on delay circuit lost the ground wire connection to the power supply board.

Re: Step-down Transformer, AVR thread (and Variac)

I plugged the AVR, turned on the switch. Then tapped the wire onto the GND net, for a fraction of a second only. The LED turned ON while I did that.

A good sign.

Went ahead and soldered the wire. And the AVR is working again! :wootrock:

Re: Step-down Transformer, AVR thread (and Variac)

Wow! :groupwave: so para saan yung wire, Sir?

I plugged the AVR, turned on the switch. Then tapped the wire onto the GND net, for a fraction of a second only. The LED turned ON while I did that.

A good sign.

Went ahead and soldered the wire. And the AVR is working again! :wootrock:

Re: Step-down Transformer, AVR thread (and Variac)

Wow! :groupwave: so para saan yung wire, Sir?

Its the supply ground. The negative terminal.

Re: Step-down Transformer, AVR thread (and Variac)

@ Joey81,

Sorry I couldn't get back to you as early as possible. Glad to know that things are OK with your AVR. Yes the wire is for ground as evidenced by the IC timer dot on the Hitachi HA17555. Forgive me if i'm wrong but isn't that C1 (Electrolytic type capacitor) instead of C2 (w/c is non polar) that you are referring to? Nevertheless I am glad that all is well. Please observe the vibration that you mentioned when operating the SCMS. Was it a vibrating or humming sound you heard? If it is humming then you may want to have the coil checked for it's insulating varnish if it's still as packed as when you originally got it or have them ground test the unit to be safe. Sometimes it happens w/ transformers. Just bring it to any local electronic service outlet for a quick test to be sure. They probably will charge P300 - P500 for the testing but that's better than not being sure. Good luck kaibigan!:)

Re: Step-down Transformer, AVR thread (and Variac)

Its the supply ground. The negative terminal.

negative terminal lang pala at pinakabahan pa kayo. hehehe

Sir, kailangan din pala maging electrician kung mahal na mahal mo mga power tools noh? :obvious:

Re: Step-down Transformer, AVR thread (and Variac)

negative terminal lang pala at pinakabahan pa kayo. hehehe

Sir, kailangan din pala maging electrician kung mahal na mahal mo mga power tools noh? :obvious:

kung mahal na mahal mo power tools mo, di mo isusugal yan....

Re: Step-down Transformer, AVR thread (and Variac)

hahaha Sir, san pala shop nyo? 🙂

kung mahal na mahal mo power tools mo, di mo isusugal yan....

Re: Step-down Transformer, AVR thread (and Variac)

Hello Guys, Im glad I found this site for fellow pinoy DIY'ers.
Amazon has a promo on Bosch, DeWalt, Makita, Skil and Porter-Cable tools. So, looking to build my own set of tools (first time), I went shopping spree on mostly Porter-Cable tools - Di masyadong mahal compared sa green and yellow brand. Also bought the Hitachi Miter saw with laser and Graco Magnum X5 airless sprayer. I will all be shipping them to Isabela.

Which bring me to my concern. The highest amp I have is the 15 amp miter saw. Based on what I read here, can I assume that I am safe in using a 3000 watt step-down tranformer? (I hope to hear based on your experience of similar wattage) Would you be so kind to recommend a brand and where / how much it costs? I'm reading about STAC's reliability, but I can't find any information online nor vendor based in Manila. I am hesitant to use those chinese made transformers - daming negative reviews ng Goldsource / Simran / Seven Star sa Amazon. I have narrowed my options on Panther EI Transformer (not the toroid) and this STAC toroid transformer. I hope STAC's price is not as expensive as the Panther in same watt capacity.

Re: Step-down Transformer, AVR thread (and Variac)

Hello Guys, Im glad I found this site for fellow pinoy DIY'ers.
Amazon has a promo on Bosch, DeWalt, Makita, Skil and Porter-Cable tools. So, looking to build my own set of tools (first time), I went shopping spree on mostly Porter-Cable tools - Di masyadong mahal compared sa green and yellow brand. Also bought the Hitachi Miter saw with laser and Graco Magnum X5 airless sprayer. I will all be shipping them to Isabela.

Which bring me to my concern. The highest amp I have is the 15 amp miter saw. Based on what I read here, can I assume that I am safe in using a 3000 watt step-down tranformer? (I hope to hear based on your experience of similar wattage) Would you be so kind to recommend a brand and where / how much it costs? I'm reading about STAC's reliability, but I can't find any information online nor vendor based in Manila. I am hesitant to use those chinese made transformers - daming negative reviews ng Goldsource / Simran / Seven Star sa Amazon. I have narrowed my options on Panther EI Transformer (not the toroid) and this STAC toroid transformer. I hope STAC's price is not as expensive as the Panther in same watt capacity.

I'm using the Samwon 3000-watter with a 15-amp Hitachi. So far no problems, other then the cold solder that came loose due to vibration.

Re: Step-down Transformer, AVR thread (and Variac)

Thanks for the info Joey81. Appreciate it.

Re: Step-down Transformer, AVR thread (and Variac)

So because of the good feedback here about Matsunaga Stavol AVR, I scour the internet and found a used one for about 10,000 php including shipping. What surprised me was I actually got a surplus equipment from a US Airforce. That speaks for the high precision and quality of these Japan-made AVR. I've included the photo to show the original rolling crate to which the AVR is encased. Unfortunately though, none of the shipping boxes fits the rolling enclosure, so only the Matsunaga Stavol AVR will find itself in Isabela.
I also measured the no-load power and it consumes 40W. Guess my tools will happy with their "new" partner.

Re: Step-down Transformer, AVR thread (and Variac)

This is what I got to power my Bosch 4100 table saw. Surplus Variable Transformer 3KVA.

Re: Step-down Transformer, AVR thread (and Variac)

Hanep!

May selector para variable voltages? The way it looks, bullet proof.