5 knob Deluxe Memory Man Blue

[Vitrolin]

when helping a friend cleaning his work shop i found this beauty, he has newer played music, and doesn't remember were it comes from, so he gave it to me.
i replaced the power cord and it works magnificent

but i am a bit curious about the age.

I have newer before heard a blue 5-knob, the PCB is numbered EH1343B



Guts


PCB no


by the way i'm in europe


edit: image fix

[Scruffie]

Pictures aren't working here but colour me intrigued.

[GiovannyS10]

No images working 

[mth5044]

They are posted to a not-publicly shared dropbox. Try imgur for posting pictures.

[Vitrolin]

images fixed.... it took a while

if someone has a schematic or calibration instruccions would be great found something here but its another version
http://www.davidmorrin.com/home/trouble/troubleeffects/electro-harmonix-memory-man/eh-7850
http://www.davidmorrin.com/home/trouble/troubleeffects/electro-harmonix-memory-man/eh-7850/eh-7850-calibration
would be nice to get it running as good as possible...

[Scruffie]

Looks exactly the same as other models, just a different PCB layout and silk screen colour.

Google will get you the schematic and calibration.

[Vitrolin]

Looks exactly the same as other models, just a different PCB layout and silk screen colour.

Google will get you the schematic and calibration.

see links postet above

i thought maybe somebody already had something on this PCB, before i start tracing, i guess the calibration procedure is the same

[Mark Hammer]

I'm repairing a 5-knob DMM right now that uses this exact PCB - black and red, but no blue.  The posted pics were very helpful, since one of the transformer leads going to the board had fractured and I needed to know where it connected.  The lead from the input jack also fractured - one of the casualties of solid-core wire - and I'm in the process of trying to figure out where to reconnect it.  I wasn't measuring any supply voltage initially, but replaced the 220uf and 100uf caps in the power supply, and all voltages read appropriately now.

I'm curious about the empty 16-pin dip slot that sits unused.  Does anyone know what was supposed to go there?  Was this possibly for a 3rd MN3008 BBD when the MN3005 were is short supply, or was it for something else?

[Scruffie]

It was for a 4049 clock buffer before they realised the 4047 could drive two 3005 on its own, if you look at the factory schematic it's on it and just crossed out.

[Mark Hammer]

I have a bunch of DMM schematics, but it would seem that's not one of them.  Link?  Never mind.  Found it.

[Mark Hammer]

So, the power supply would appear to be the problem.  Specifically, it looks like I'm going to need a replacement for the 2N6117 unijunction being used as a form of regulator.  I can't find a replacement for it in any of my replacement guides.  Not even an NTE/ECG unit comes up.

Any ideas?

[Rob Strand]

2N6117

Maybe checkout 2N6027/2N6028 (PUT) for availability.
Then check the datasheets.

There's also UJT's 2N2646 but I'd have to look closer at the ckt to see if it would work.
2N2646 was what people used before NE555's.

I think the 1964 GE Transistor handbook (downloadable) had some nice info in these devices.


Are you sure it's not 2N6111, just a transistor? That makes more sense for a regulator

[Slowpoke101]

Agree with Rob here. 2N6027 is pretty damn close to a 2N6117.
Other equivalents are MPU132 and MPU232 which are just as rare as a 2N6117.

Had a look at the schematic. Shows as a 2N6111 transistor being used as a series pass regulator.

[thermionix]

I know nothing about UJTs and PUTs, but I have one each of 2N6027 and 2N4870 that you're welcome to Mark.  Shipping to Canada would be on you though, and I expect not worth it unless there's no stock elsewhere.

[Rob Strand]

Had a look at the schematic. Shows as a 2N6111 transistor being used as a series pass regulator.

That's makes more sense.   Serious doubt that's a PUT.

[Mark Hammer]

Admittedly, the legending on the unit is very ambiguous.  Look at it one way and it's a '1'.  Tilt your head a bit and it's a '7'.  But I suppose the topography of the circuit should be the tiebreaker.

[Rob Strand]

Here's a much cleaner version,  pretty clear it's a 2N6111,

[PRR]

Not a unijunction. Dumb regulator.

It's not 1980 anymore. Put in a LM7915 plus a diode.

If you can't get a '79 where you live, "any" jellybean PNP will work; but the '79 is the better solution.

[Mark Hammer]

 Good advice.  I'm confident the owner won't be anal retentive about it.  Got a drawer full of '79s.  I'll be alright.

[StephenGiles]

Is this for the DMM you are working on Mark?

DELUXE MEMORY MAN WITH CHORUS AND VIBRATO ALIGNMENT PROCEDURE  (8/1/78)
Plug unit into 115V 60Hz. and set feedback and chorus/vibrato fully CCW, blend fully CW, delay fully CW and power on. The pilot light should come on but not the overload light. Connect the scope to pin 2,4,6,10,12, or 15 of the CD4049 and observe the square wave period. It should be between 120 and 140 usec. (add c across 240pf if necessary). Set the delay fully CCW; the period should now be between 8 and 10 usec. Set the delay to the middle of its range. With the switch in the chorus position slowly bring up the chorus/vibrato control, watching the square wave. The period should decrease slightly and become modulated at a rate of slightly less than 1Hz. At max. chorus setting the period should swing approx. 10% of its average value. Set the switch to the vibrato position. The modulation rate should go up to approx. 4Hz. Set the chorus/vibrato control fully CCW. Connect a 250Hz signal of 500mv p-p to the input and adjust the level control for the same level at pin 6 of the NE570. The level at pin 7 should be between .95 and 1.4 V p-p. Watching pin 7, increase the level. The overload light should just begin to glow at about 1.4V p-p and should be almost as bright as the pilot light at about 2.3V. No distortion should be visible in the signal - at this point. Look at pin 7 ot the first MN3005 and turn, down the level for a signal of 1.5V p-p. Slowly increase the input frequency. The response at pin 7 of the MN3005 should be flat up to about 9OOHz, rise to a max. of about 2V p-p at around 2.5KHz at which point the overload light should glow dimly, drop back to 1.5V p-p at_ about 3.8KHz and roll off sharply above this. Set the frequency back to 250Hz, the 2nd trimpot at about center, and connect the scope to pin 7 of the second 4558, which is also the wiper of the first gain trimpot. Increasing the level setting as necessary, set the first bias trim for maximum p-p undipped signal, then at a lower signal level set the gain to unity (output level = input level). The output level before clipping should be 3.8V p-p or greater. Vary the delay over its full range and if clipping becomes very unsymnetrical at either end, trim the bias a bit for a good compromise over the range. It is normal to see alot of clock noise at the highest frequencies. The second MN3005 is aligned in the saw way as the first , except that the clock balance trirs is carefully set for aiin. clock frequency at its wiper at maximum delay (nin clock frequency) setting. This should be done before fine trimming the bias for symmetrical clipping and again after the bias is finally set, with the input signal to the unit disconnected and the scope gain high. Set the 2nd gain trim last looking at pins 14 and 15 of the NE570 and setting this trim so that the signal is equal in level to that at pin 7 of the 570. If this can't be done, go as far as the trimmer permits and re-adjust the first gain trim to achieve it. Set the level so that the overload light is on dimly, looking at the signal at pins 14 and 15 of the NE570. Set delay to max.(CW) and vary the input frequency from 40Hz upward. The signal should be unclipped and clean over the range. The response should show no peaks, but be flat at about 2.5 KHz and -3db,(x.7) at about 3.2KHz, where only a small amount of abiasing ripple of the waveform should be visible. Set the delay to min.(CCW), The response should now have a peak of about +3db (x1.4) around 2.5KHz and roll off sharply above 3.5 KHz with no trace of noise or abiasing.
Set the input frequency to 250Hz and adjust level for 1.0V p-p
at pins 14 and 15 of the NE570. There should now be between .6 and
.8V p-p at pin 10. Set delay fully CW and disconnect the input.
Looking at the unit's output and overload light turn the feedback
fully CW. Touch-the input to introduce a transient signal. Runaway
oscillation should occur with the overload light flashing brightly.
Set feedback fully CCW and blend to center. Reconnect input and observe
output as input frequency is varied slowly. It should show a peak
and null (comb filter)response. Check that the footswitch connects
the direct signal to the output when it is thrown and that this
signal is always present at the direct output and is controlled
with the level control.
The test and alignment is now complete.