Sep 9

Sun 404 Tester. I need this like a hole in the head

@Edinmass egged me on (he's good at spending other peoples money). I've been looking for a distributor tester for the last 18 months or so. Most need to be shipped or worked on. Finding a working 504/404 Sun 45 minutes away forced my hand.

Sep 9, 2026

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Replies (22)

· Sep 9

Unlike the older mid-century "Master Models" or battery-dependent SDT units, the 404 brought some nice design upgrades including the elimination of the internal batteries and 4k RPM distributor speed.

Our buddy Ed heavily pushes you to buy a 404 or 504.

· Sep 9

But the thing that really sold me on this is that it has the ingnition simulation module. This slides in to the distributor drive and demonstres how the ignition system works. There is some debate about the purpose, strickly educational or useful for testing.

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· Sep 9

Among the the stuff included was a Champion plug scope.

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· Sep 9

YouTube ↗

· Sep 9

Never heard of this. Now I want one.

· Sep 9

The 504 has the condenser tester and gauge. Otherwise it is identical to a 404.

· Sep 9

Love it.
I'd love to find a Sun in working order.
I have an Allen 22-250 synchrograph which is functional but needs a little work.

· Sep 9

Allen equipment is great but it doesn't have the support system that Sun does. Of course, if the one guy behind Paramount calls it quits we will all be in the same boat.

· Sep 9

You won't be sorry on this purchase!!!

· Sep 9

I’ll store yours if you store mine.

· Sep 9

Paramount rebuilt that for you or did you buy it like that?

· Sep 9

I love that I'm filling my brain with these useless facts.

Key Differences Between the Sun 404 and Sun 500Power Requirements:

The Sun 404 is completely battery-free and runs entirely on 120V AC wall power.
The Sun 500 requires internal 1.5V batteries and external 6V/12V batteries to run its meters.

Meter Layout: The Sun 404 features a 3-meter layout grouped tightly on the right side. The Sun 500 features a 4-meter layout split across the panel.

Form Factor: The Sun 404 is primarily a compact benchtop unit. The Sun 500 is typically a large floor console integrated into a rolling cabinets.

Spindle Speed: The Sun 404 has an upgraded motor that spins up to 4,000 RPM. The Sun 500 baseline models max out around 2,000 RPM.

Generation: The Sun 404 is a newer, modernized unit. The Sun 500 is an older platform originally designed in the 1940s and 1950s.

· Sep 10

So my 404 doesn't have the Coil/Condenser tester but I have the matching full tester from Sun. Slightly earlier than the distributor tester but it has been restored and everything works.

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· Sep 10

I’m a Sun fan and have a small collection of their stuff.

· Sep 10

Look at us John! A couple of posers. Does your work?

· Sep 10

Webster Dictionary: “POSER”=John Bloom….

I have no idea if it works….. it scratches my Dr Seuss itch/vibe.

Another note, today is my last day of working. I’ll be retired when I wake up tomorrow morning. Let me put “testing all all my sun equipment” on my to-do list in retirement.

(edited)

· Sep 10

If you want something done you give it to a busy man.

· Sep 11

John, congrats on the retirement! I can't imagine what that would be like. Maybe I'll try it before I die.

· Sep 11

The concept is strange to me, I’ve probably had a job since age 12/13….. an “exit” walked into my life that I didn’t create, and I felt like it was too good to let it pass.

I’ll start planning what’s next over coffee in the morning. Lots of hobbies, interests and family to fill up the calendar. My wife and kids don’t see retirement lasting long…….

· Sep 10

Here is a topic I did when we set my Royale distributor up on an Electro Products tester. Basically the same as using the Sun.
https://reoroyale.com/forums/7/topics/11938

· Sep 11

Good for you, finally getting a distributor machine. Looks like you got a nice one. Now you'll wonder how you ever got along without it.
I got an Allen synchrograph about 30 years ago at an auction. The cabinet was locked and it didn't come with a key. When I got it home and ground the lock off, there was an old tobacco can full of coins . It had more money inside than what I paid for the machine! That made me very happy.

· Sep 13

Look at the Chicagoland Packard club having a tech session this weekend with the Sun distributor machine. My kind of guys, wish I had attended
https://www.facebook.com/share/p/1J2XtsmJwq/