Hartke HA350 issue with SSM2018

[blindboybenton]

Good day gentlemen
This one has a few issues
At the gig the owner Plugged the speaker into the send and return by mistake
and not sure the rest the fuse blew.
He continued to use a spare bass head
When i get it i replaced the fuse and used the Lamp limiter i can see that the amp is drawing way too much current.
Disconnected the amp board (power and signal ). I can then power up the amp
so i know i have faults with the power amp
hartke_ha3500_power_amplifier_sch.pdf
Testing the pre amp to confirm that status the signal is all mush
traced into the SSM2018 all good , but output is mush

SSM2018 is no longer available , I can buy from Crapbay from china
with current state of affairs and time delay and very high cost
there seems to be no alternative.
Had a look on the net can't seem to find an alternative

has anyone found one

open to idea's
BBB

[Enzo]

I have a 2275 in stock still. And I have an Ensoniq main board for an old ESQ1, that has Curtis chips and a number of SSM types.


Couldn't hurt to contact Hartke and see if they have some workaround they use.

[blindboybenton]

Thanks Enzo

The Hartke dealer in the UK are not that good tend to be just board suppliers
I will contact them, The customer does have many amps, so i might just order from china via ebay
and it can wait
BBB

[g1]

I doubt that the chips from China are legit, same for any obsolete chips that can't be found anywhere else.
Even used legit IC's are usually preferable.

[The Dude]

^^^^^^ Agreed. Don't bother with Chinese fakes! You're asking for a headache.

[blindboybenton]

oh you guys had trouble with them ??
well ive ordered it from china already.
we shall see.

BBB

[blindboybenton]

Good morning/afternoon
Well after 6 weeks the part arrived. Fitted and the problem is still there.
If my memory is correct ... No change from the original fault
Signal in via the 18k R127 is ok Out at pin 14 is not correct, But at switch on the signal at pin 14 is perfect
for about 2 -3 seconds then see below

I removed IC105 and checked still same

Output to power amp is

Due this lock down i can't get access to my workshop for more than 2 hrs per day. I plan to fitted the original ic back and see.

The third picture was one i attached and then deleted , but its still there. its another picture of output from pin 14

Stay safe
BBB

[Jon Snell]

I would lift C131 and check for issues. IC107 is the next possible but if you plug speakers, a low impedance load, into the effects loop, it will have no issues from damage as the components are protected against short circuits etc. Have you been told the whole story I wonder.
Check the +-15 rails are healthy.

[blindboybenton]

Who knows about the story, He told me what he did. All voltage rails are good
with the repair being in the state it is with output stage faulty too. I may just return, he was not to keen to pay the bill in the 1st place
BBB

[Jon Snell]

Shame to give up but if there are issues, it may save the headache later down the line when something else fails.

[blindboybenton]

well you were bang on with ic107. cut the 220uf cap out turned on and it was perfect. I have replaced the ic and cap. all good, now i have to turn my attentions power amp
I think he plugged the output into the send or return
BBB

[Jon Snell]

I have found these to be a sturdy power stage. Lift C211 and check the IC is OK before digging in too deep.
What is the issue with the amplifier? Any good with injecting a signal on R254 with C211 lifted.

Just saw your last post. Excellent news.

[blindboybenton]

Many thanks People

Its all done. It wasn't SSM2018 turned out to be a IC107 . Just replaced Q308/309/310 in power amp . All working and is now back together