Hartke HA2000 Schematic Needed

[telecaster]

Trying to signal trace and the schematic(s) I got from Hartke don't match. My main board is 4005109110, and the Send/Receive board is 4005194001. I am most interested in the preamp schematic, mine has different ICs.
IC101 = 2068
IC102, 104, 105 = 4558
IC103 = N27542
IC106, 107 = M5227
IC108 = 5532
Any help muchly appreciated

[Jazz P Bass]

Can you post the schematic that you have?

It sounds like you have one of the very early ones.

These are the ic's in your amp, correct?


IC103 is giving me a headache. N27542?

IC106 & 107 are the EQ chips.

The rest of the ic's, are simply opamps.

[telecaster]

Attaching the schematic that doesn't match my preamp board

Jazz P - yes the IC's I listed are the ones in my amp. I may have misread the number off IC103, will verify tomorrow.

Can you post the schematic that you have?

It sounds like you have one of the very early ones.

These are the ic's in your amp, correct?


IC103 is giving me a headache. N27542?

IC106 & 107 are the EQ chips.

The rest of the ic's, are simply opamps.

[Jazz P Bass]

As shown, other than the opamps being different, does your board come close to the posted schematic?

The correct identification of IC103, the compressor chip, may help.

I am thinking the HA3500, older EQ version, may be closer.

[J M Fahey]

What exactly seems to be the problem?
What symptoms?
What are you trying to solve or repair?

And yes, the only "mystery chip" there is IC103, a practically datasheet application of compressor SSM2018
http://www.analog.com/static/importe...ts/SSM2018.pdf

EDIT: the ICs in the schematic were replaced by same function, same pinout , different model, that does not change the way the circuit works, so don't worry about that.

By definition, "all Op Amps are functionally the same" and slight differences appear only when used at the very extreme of their range, such as with very high frequency loads plus maximum gain or with very low level signals, where noise may become a problem, but other than that , "they are all the same".

[telecaster]

Not even close

Jazz P - no, the posted schematic goes through IC101, shown as NJM072D, then to IC111 - my board only goes to IC108. I get that the op amp type can differ, but when I want to signal trace, it helps to know which IC is which. I'll update the compressor chip part info when I get to the shop.

QUOTE=Jazz P Bass;367219]As shown, other than the opamps being different, does your board come close to the posted schematic?

The correct identification of IC103, the compressor chip, may help.

I am thinking the HA3500, older EQ version, may be closer.[/QUOTE]

[telecaster]

UPDATE: IC103 is in fact a 2018, sorry for the confusion. So I will follow Juan's guidance that all op amps are functionally the same and try to map which IC is which in the signal chain, assuming the signal flows left to right.
Juan - the tube channel is weak and ultra-hissy. Solid State channel is all good.

[telecaster]

Jazz P - my board does not match the schematic at all. The discrete components and interconnects are different right off the inputs. I pulled the board and started to trace, very time-consuming. If you have any other schematic, I'll take a look and hope for one that matches.

[Jazz P Bass]

There is not much to the tube circuit that is not common to the SS side.
The tube itself & it's associated components.
And two IC halves.

I would start with the tube.
Clean, lube & retension the socket pins. Resolder the socket.
Not it, try a new tube.

If it is tube related you should see the problem on the cathode output pin.
Not there, keep going to the opamp output.
Not it.
One opamp half left.

[Jazz P Bass]

Try this schematic.
It may be close.
Although I can see already that the compressor IC 103 is labeled IC109.

[J M Fahey]

Part ID number at the drawn schematic may differ, suppose in a revision they added a 100pF cap right at the input so all other caps get ID raised by 1 ...... and so on.

So in fact part ID which is random, designers can use any number they wish, so far as none repeats (and I have seen even that ) so it's not that significative.

But designers have their personal quirks and pet ideas and tend to repeat them time and again, what I've seen of that schematic screams "Hartke" and basic blocks should be very similar (even the same) across different models.

Please download this .gif showing the tube preamp section, open it in some graphic editor software (download Irfanview if you have nothing else) and place a small new label besides every part, with the designations printed on your PCB .

Much faster than redrawing everything

Repost edited schematic (give it another name so Forum accepts it) and we'll be able to suggest specific readings.

I'm quite certain that the tube stage is the same in all Hartke amps ... except the one which clones a full Fender preamp.

Just curious, because you can test this without a schematic: what happens if you turn amp on and rise "Tube Volume" without the tube inserted?

What if the tube is inserted but tube volume goes from 10 to 0?

Those 2 tests alone already tell us something.

[telecaster]

How it's really wired

I’m attaching a hand-drawn schematic of how this preamp board is actually wired. I initially asked for any other schematics because nothing made sense using my previously posted HA2000 schematic, not even the tube and surrounding discretes. The one Jazz P Bass posted was closer, for example it also had the tube as the first gain stage with an op amp stage between the two tube stages. But there were enough other differences to warrant pulling the board and following circuit traces/land patterns.
One other background note: I had already tried a new tube, retensioned and cleaned the tube socket, and checked DC voltages at the tube pins accessible between the socket and board.

Late Wednesday I put everything back together and was signal tracing for 1/2 hour when the amp started to hum (master and solid state volumes down, and tube volume up). I immediately shut it down and noticed a slight burnt electronics smell. So now I have another problem to find and fix before I can get back to the original one.

[J M Fahey]

Thanks for taking the trouble of tracing and posting.

Immediately I am disliking a lot C113/C114 in series, completely underrated for their job.

Measure DC voltage (relative to ground) on the node R118/C113 and C114/Tube Volume pot .

A node is any line or point which joins 2 or more parts which so are at the same voltage by definition.

Post results.

[telecaster]

Fixed!

After I drew the schematic, the amp developed a short, which I eventually traced to IC101 (+18V to - 18V measured 28 ohms on that IC!). Before the short, I had verified the signal was getting lost between V1(B)'s output and V1(A)'s input (IC101A was in between the two stages). I replaced IC101, which fixed the short, and then the tube channel was working fine! Thanks to Jazz P Bass and J M Fahey for the schematics and tips.