Furman power sequencer.

[George S.]

Got the first of two Furman PS-8R Series II in and on the bench.
While back Gene asked how I was going to switch the system on and off once it's set up with a four way active crossover.
My solution is to run two of these power sequencers.
Unit is clean and works.
Going to recap them if I can find the specs and replacement for that short electrolytic beside the toroid.
It's probably a low ESR.
A general purpose cap probably won't work there.
Looks like a nice unit with decent build quality.

 

[J!m]

Furman made decent stuff... pretty much every pro rack has one.

 

[George S.]

Yup, decent quality, not great, but decent. Built to a price point.
The big cap is a TW Bor 270uf 250V. Taiwan manufacturer with facilities on the mainland.
AKA Bor Hurng Electronics Co.
Unfortunately there are no series markings on their caps. Appears color and the marked temp rating determines the series.
Requires more digging for info, though it appears a low ESR, high ripple cap suitable for a SMPS will work as a replacement.
Once the other unit arrives I'll see what I have and order caps.

 

[grapplesaw]

George
I have three of these units to add to my system. With balanced interconnects sequencing is necessary in my setup’ These units can have a momentary or constant remote switch. I also bought two promax m4000 sequencers, all the same company, which are blue tooth operated . They however are not as good quality. After reworking both they have been designated to the lab for power switching my meters and stuff I have here variou items of theirs all good but as you can the Paramaribo has light relays o two channels

 

[George S.]

Glenn, very cool. These are definitely nicer than using a couple of power strips.
I really like hearing the relays as the sequence proceeds for start up and shut down.
I set the internal jumpers so it powers up and down in sequence from the small push button on the front.
I also have the remote wiring set as momentarily to do the same.
Manual says two units can be wired together via remote to act in tandem. Going to try this once the other unit arrives. Hopefully one push button press on either unit wil activate both units.
The big cap appears to be a TW Bor TRM series snap in. Data sheet says 85degC, 2000 hrs, +-20%, explosion-proof. Suited for SMPS, communications equipment, other electronic products.
Should be easy to sub in a Nichicon with better specs like 105 deg and 3000 hrs.
There's also four small Jamicon and a medium NZL axial on the logic board. I'll replace those also.

 

[wattsabundant]

Does this thing just turn on outlets in a sequence? If so it seems awful complicated. I could do that with a 555 timer and a counter chip.

Multi stage linear filtering? I hate to rain on a parade but it sounds like gobbledygook marketing to me. A ferroresonant transformer will beat the pants off any filter and provide line voltage regulation.

 

[George S.]

Does this thing just turn on outlets in a sequence? If so it seems awful complicated. I could do that with a 555 timer and a counter chip.

Multi stage linear filtering? I hate to rain on a parade but it sounds like gobbledygook marketing to me. A ferroresonant transformer will beat the pants off any filter and provide line voltage regulation.

Yup, lots of info on the web that's pro and con about these. Some say it's a glorified power strip and others say it works great in the studio for reducing voltage spikes and line noise.
The red rocker switch on the front turns the unit on and makes the front AC outlet and right rear AC outlet hot.
Pushing the front start sequence button or using the remote function starts the sequence function that turns the other three outlets on or off with a adjustable time of 1 to 7 seconds between each outlet.
From my reading, a balanced isolation transformer was the preferred route to go, but I can't justify spending that much money, as I don't perceive any issues with my homes electrical service.
I have these to replace power strips.
Got the second unit in. It has a fault on the logic/ relay board. Going to get to work and fix it.
These aren't something I really need. Just thought they're a cool accessory and better than the old power strips for running a large 4 amp rack.

 

[George S.]

The bad board is powered by a +and- 19VAC center tapped transformer. It's good.
The on board regulator is a 7812. It's good.
All diodes, resistors, and 3 tantalums check good.
Started checking the 2N4401 and 2N4403 transistors in circuit with the Sencore, and appears 3 are shorted emitter to collector.
The Sencore manual says it tests accurately in or out of circuit.
Going to pull those 3 and test out of circuit.

 

[George S.]

All three transistors test out of circuit excellent with good gain. Been wondering about testing in circuit. Now I know!

 

[laatsch55]

Yep, when in doubt, pull the little bahstyards...

 

[George S.]

Back at it. The board has four SIP(single inline packages) on it, never seen these before.
Turns out they're a resistor network.
They're all 8B series which means 8 pins, with a single resistor between pins 1+2, 3+4, etc.
They all test good.

 

[J!m]

I had a similar bridge rectifier in my Micro BL-91. I replaced it with a way-overrated square package up off the board.

 

[wattsabundant]

Is there a schematic available? The 3 transistors likely control the 3 relays.

 

[George S.]

Haven't found a schematic. I pulled every transistor from the board and retested. All transistors have excellent gain and no leakage.
All the analog components test good
That leaves a Phillips made flip flop IC and a TI opamp. They're like a $1.50 for the pair so I ordered extras and am just going to replace them and see what happens.
I'd like to test the ICs out of circuit, but I need to get a bread board. One of those multitude of things I never got around to doing because of work.

 

[Gepetto]

Haven't found a schematic. I pulled every transistor from the board and retested. All transistors have excellent gain and no leakage.
All the analog components test good
That leaves a Phillips made flip flop IC and a TI opamp. They're like a $1.50 for the pair so I ordered extras and am just going to replace them and see what happens.
I'd like to test the ICs out of circuit, but I need to get a bread board. One of those multitude of things I never got around to doing because of work.

My money is on the Philips IC...

 

[George S.]

Got the Budwig TF8T feet installed on each chassis while I wait for parts.

 

[grapplesaw]

George
I had two Paramax no work for me
I used a air solder iron to go over the board and found that somewhere there was a cold solder joint

I just Re soldered all through board joints as I could not fine the exact problem as well key components. Somehow that fixed then after I had changed the two smaller relays.

you may have similar issue if you cannot find a bad device

 

[George S.]

Yup, got it. Luckily no surface mount on these.
They were wave soldered on one side only, even though they're double sided with plated through holes.
And, they used a very high temp lead free solder. Probably somewhat brittle and prone to cracking.
Had to mix a little leaded solder into the joints before desoldering with the Hakko vacuum station.
I plan on soldering and resoldering all components on both sides of the board.
Note mine are not the Pro 20 amp versions with the key switch. I got the 15 amp versions as I'm using 15 amp outlets, and didn't want to switch the plugs, use a adapter, or change the outlets.
Eventually I'll upgrade to 20 amp outlets and find some Pro versions to rebuild.
I can easily use the 15 amp versions in the work room and garage.

 

[wattsabundant]

Lead free solder sucks. Been there, dealt with the aftermath.

 

[George S.]

Working on the boards. They glued one axial cap onto the logic/relay boards. Removing it pulled some solder mask off. Coated it with clear nail polish after a good alcohol cleaning.