Menu

Show posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Show posts Menu

Messages - cdparady

#1
Amplifier Discussion / Re: Jordan Two/01 Repair
December 20, 2022, 08:02:01 AM
Tremolo/Reverb Board Details

Here are some pics that should help .....

You cannot view this attachment.
You cannot view this attachment.
You cannot view this attachment.
You cannot view this attachment.
You cannot view this attachment.
You cannot view this attachment.     

#2
Amplifier Discussion / Re: Jordan Two/01 Repair
December 19, 2022, 09:20:42 AM
Update #4 - Final Update

Final product, rebuilt the cabinet to look somewhat respectable !!

If anyone reverse engineers the schematic, please post !!

Merry Christmas all.

Chris P.

PS - For you OCD folks like me, bottom fully vented, replacement knob coming, owner is going to paint ;)

You cannot view this attachment.
You cannot view this attachment. 
#3
Amplifier Discussion / Re: Jordan Two/01 Repair
December 19, 2022, 09:11:43 AM
Update #3 - Preamp & Tremolo/Reverb Boards

Board Location - Tremolo/Reverb Board Top, Preamps Middle & Bottom

You cannot view this attachment.

Tremolo/Reverb Board

You cannot view this attachment.
You cannot view this attachment.

Preamp Boards (Identical)

You cannot view this attachment.
You cannot view this attachment. 
#4
Amplifier Discussion / Re: Jordan Two/01 Repair
December 19, 2022, 09:06:50 AM
Update #2 - Worked through the amp board last week......

Testing Notes:

- Output clipping 1/2 way through the negative cycle
- DC Offset -6VDC
- Signs of prior repair, one pre-driver replaced at some point and at least one diode
- ECG181 (PNP) Running Hot At Idle

Repairs:

- Filter Caps & Drivers Tested OK
- Replaced Input Cap & The -9VDC Electrolytic (Note "+" Sign Silk Screen Wrong on Board)
- Bridge Diodes Tested Fine, Replaced 5 Others
- Several of the small TO92's tested bad, so I swapped them all out
- Pre-drivers were unmatched from prior repairs, replaced with higher power MJE TO225's
- Details Attached on all of the components, originals, pin outs, replacements

One important note, the right side of the board (bottom view) near the -9VDC pins to the pre-amp boards and tremolo/reverb board does not share a common ground trace with the left side of the board....the return path is through the chassis.  Whether that was a intentional design or not, who knows.  That was the root cause of the DC offset issue, bad ground.

Final Test:

- Board came back up in very nice shape, scope trace attached
- Measured 16 VAC RMS just before clipping into an 8 Ohm Load, so 32 Watts RMS
- DC Offset Settled in at about 250 mV DC
- Both Preamp Boards Tested Fine
- Tremolo Tested OK, Reverb Tank long gone so no Reverb

Will post pics of the preamp boards (both the same) and the Tremlo/Reverb board.

Happy reading !

You cannot view this attachment.
You cannot view this attachment.
You cannot view this attachment.   















- Power Transistors, Main Filter Caps
-
#5
Amplifier Discussion / Re: Jordan Two/01 Repair
December 19, 2022, 08:24:03 AM
LOL that someone noticed the cap polarity ..... !!

It was definitely in backward from the factory, silkscreen wrong, factory install wrong.   Corrected it on the new install.

Transistor details coming on the next post.
#6
Amplifier Discussion / Re: Jordan Two/01 Repair
December 15, 2022, 06:56:51 PM
One more update for today....AC Power Cleaned Up

- Death Cap Removed
- New 3 Wire Grounded Cord
- New Fuse Holder
- New Power Switch

Note, accessory outlet was shaky, gutted it and bypassed it.

Made some progress on the amp board, will post another update in the next few days.

You cannot view this attachment.
 

#7
Amplifier Discussion / Re: Jordan Two/01 Repair
December 15, 2022, 06:51:12 PM
Update - Couple of additional pictures of the amp board cleaned up.

- Amp is Dual Rail +/- 30 VDC
- I believe Class AB 
- Looks like one pre-driver replaced in the past

More to follow.....

You cannot view this attachment.
You cannot view this attachment.
You cannot view this attachment.
You cannot view this attachment.
You cannot view this attachment.
#8
Amplifier Discussion / Jordan Two/01 Repair
December 06, 2022, 06:03:06 PM
Thought I would start a fresh thread on this, I posted looking for a schematic a few weeks back.

Just getting into the amp, here are a few starting notes & pics.....
 
- Speaker cabinet long gone
- No schematic in the cabinet, but bonus on the wiring diagram (pic below)
- 2 TO3 Outputs ECG210/ECG181
- Amp board looks toasty, other boards in great condition
- Death Cap Still in Place (!!)

I will add some additional photos as I progress, goal is to get it cleaned up, operational & safe.

Thx, Chris

You cannot view this attachment.
You cannot view this attachment.
You cannot view this attachment.
You cannot view this attachment.

You cannot view this attachment.       

     
#9
OK will do.....
#10
Yah figured....

I have not gotten into it yet, guessing final blown but we will see.

Thank you !
#11
Schematics and Layouts / Jordan Two/01 Schematic Needed
November 18, 2022, 09:54:30 AM
If anyone out here there has a Jordan Two/01 schematic, I would greatly appreciate a copy !!

Trying to save one from the scrap heap.

Thanks !!