Bose L1, PS1 help needed – have official Bose Repair Manual

[gis]

I am thinking that the ”Protect” line may be latched, but I’m not sure of the proper state of the protect circuit. Could it be active high, or active low? The protect line is common to all boards.

When at least one of the "failure" lines from amps goes up, PROT line goes GND (usually PROT is +5V by R636).

[gis]

What parts do you need to find?

The transformer.
Output windings are all shorted.

[jcdillon8267]

Same here. Have you managed to find the spare parts anywhere?
I tried also buying broken PS1 for parts, but didn't find anyone.
Bose told me they will not service the PSU anymore.

I gave up, I sold the working unit but still have the broken one.
I replaced the Bose with a new Turbosound IP 2000 paid 899.99.
Loved my Bose but way too much money to invest in a system I can't get serviced after several years. If after 10 yr. I can't get the IP2000 fixed 899.00 investment will hurt way less than 3000.00.

Do you wanna buy some used Bose parts?

[Enzo]

Did you pull that transformer and test it standing alone functionally? I expect it to have low resistance windings.

[gis]

No chance to test it.
Measured it as follows:

pin	pin	R	L
		ohm	mH
1	2	0,40	0,11
1	3	0,60	0,48
2	3	0,50	0,12
5	6	1,00	0,01
7	8	0,30	0,03
7	9	0,30	0,02
7	10	0,30	0,02
7	11	0,30	0,08
7	12	0,30	0,01
8	9	0,13	--
8	10	0,12	--
8	11	0,30	0,01
8	12	0,30	0,01
9	10	0,12	--
9	11	0,30	0,02
9	12	0,30	0,01
10	11	0,30	0,02
10	12	0,30	0,01
11	12	0,30	0,05

[J M Fahey]

The transformer.
Output windings are all shorted.

Well, they *should* !!!!!!!!!!!!!!!!!!!!!!!!!
To be more precise. must show continuity with very low resistance readings, 1 ohm or less.

Also all secondaries, taps 7 to 12, are again *very* low resistance (think 6/8 turns of thick copper wire) and *all* windings have at least one tap grounded, so they *will* show continuity to each other while mounted.
That´s why Enzo suggested pulling the transformer from the board and measuring it "outside".

I would be worried if deadly HOT (mains connected) primary windings, 1 to 6 showed any constinuity to secondary ones, 7 to 12 (and probably 0 too), but your measurements so not show that, thanks God.

Your transformer looks very healthy, and as noted above, is hard to kill , you must have *other* SMPS type problems.
Or whatever´s driven by the auxiliary supply is shorted or overloading it, try the supply on its own.

Now ... BOSE definitely flexed some muscle to design such a complex amp ... at least they *should* keep servicing it.

That said, it seems to be a commond trend, lately I have started seeing all over the place "small" Sound Guys with an harphazard mix of random powered cabinets, a mountain on each side of the stage with units from sophisticated RCF or Montarbo to cheesy SoundTech or Pyramid DJ oriented types: when I walk onstage I see all have the back panels emptied or straight pulled, replaced by a black painted plywood sheet with a couple Speakon jacks, they must certainly have added some kind of passive crossover inside, all driven by 25/30 year old incredibly sturdy Peavey 800 or equivalent, or cheap disposable $199 no name rack amps.

The whole system works forever, dead speakers or amps are easily replaced by Sound Operators themselves who only need to know how to solder, and Musicians hiring those Sound Guys are suitably impressed by speaker cabinet labels visible on the front, and are oblivious to the replaced guts, both speakers and electronics.

[gis]

I desoldered it to get the measures above.

Anyway my fault: didn't notice the common pin 11 from schematics; and yes, other components blew up (waiting ordered materials...).

[davealex]

I have a dead Power Stand for a Bose PS1 and I would like to turn these into regular speakers to connect to a power amp. I am not an electronics guy and I need some advice.

I did read the service manual so I know how to make the cables (see images below), but I do not know how to correctly connect these speakers to a power amp. I would like to connect all three speakers (upper array, lower array and bass) to a power amp but I don't want to do it incorrectly and wreck them.

What kind of power amp should I use? How many watts? What would the connections be on the power amp?

As you can see from the diagrams that I will use to make the custom cables, they specify banana clips on the power amp end, but I would just use stripped wire to power amp terminals, right? Would I twist all three positive leads together and all three negative leads together and just use 8 ohms off the power amp like a regular stereo receiver?

Here are the images I am referencing. Thanks for any help you can give me.

[davealex]

Service Manual is attached to the first post in this thread.

[davealex]

In terms of power, I did just find this in the Bose L1 Wiki L1® Classic - Bose Pro Portable PA Encyclopedia FAQ & Wiki

[Jazz P Bass]

Sorry, I deleted my post : "can you post the service manual".

You will need a crossover network to run all of the speakers from one amplifier.

The output power of each amplifier in the PS1 is rated at 250 watts.

[davealex]

Is there a relatively cheap and easy way to make/buy a suitable crossover network? Are we talking about something like this?

https://www.newegg.com/Product/Produ...B&gclsrc=aw.ds

[Leo_Gnardo]

Is there a relatively cheap and easy way to make/buy a suitable crossover network? Are we talking about something like this?

Something like, but not that. What you need is a sturdy 2 way crossover. Parts Express in Ohio has an excellent selection, also they have blank xo boards to which you can solder appropriate parts, build your own custom. Their house brand Dayton sells top quality inductors and film caps at reasonable prices. Have a look at what they offer & I'm sure you'll be able to construct one that does what you need.

[davealex]

Would this work?

3000 Watts Professional Power Amplifier With Built in Crossover

Connection would be like the MONO BI-AMPED SYSTEM on Page 10 of the below manual with inputs coming from our mixing board. Would this pretty much recreate what the broken Bose PS1 base does so we can use it on stage again?

http://www.wall-color.net/images/PTA3000.pdf

[Leo_Gnardo]

Would this work?

3000 Watts Professional Power Amplifier With Built in Crossover

Connection would be like the MONO BI-AMPED SYSTEM on Page 10 of the below manual with inputs coming from our mixing board. Would this pretty much recreate what the broken Bose PS1 base does so we can use it on stage again?

''

That looks like it would do, with power to throw away. Crikeys you could set your speakers on fire with 3000 watts available, way more than enough and the price makes it practically a giveaway. I'd do away with any fancy speaker wiring setups and send the sub out direct to your sub cab, hi's out direct to your column speakers.