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ITC delta noise

S

SFM-Ptgal

There's some noise on my cart machine home setup going into the carts while recording. I can describe it as similar to a random vinyl record noise, sometimes longer (pops and scratches).This happends only while recording. On playback there're no issues besides the recorded ones. The noise levels are low but they're there... Can anyone guide me to a solution? Thank you in advance.

Pedro
 
I have had the very same issue with several types of recorders. Usually it is a relay with poor continuity at the contact faces.
Is this on both channels? If so, the noise may be power supply related, but since it's only in recording, probably not.
The low levels could also be due to oxidized relay contacts. There is a product made by Caig Laboratories called De-Oxit D5.
If you can get a can, you can literally spray away most crackles, clicks, pot noises, "funny" switches, etc.
I consider it magic. It is not a cleaner, but rather, chemically removes oxides and sulfides on the contact surfaces.

Look for a relay that pulls in during record. Often they are soldered in, but have a removable rectangular plastic cap.
 
Tom Wells said:
I have had the very same issue with several types of recorders. Usually it is a relay with poor continuity at the contact faces.
Is this on both channels? If so, the noise may be power supply related, but since it's only in recording, probably not.
The low levels could also be due to oxidized relay contacts. There is a product made by Caig Laboratories called De-Oxit D5.
If you can get a can, you can literally spray away most crackles, clicks, pot noises, "funny" switches, etc.
I consider it magic. It is not a cleaner, but rather, chemically removes oxides and sulfides on the contact surfaces.

Look for a relay that pulls in during record. Often they are soldered in, but have a removable rectangular plastic cap.
Click to expand...

You should pray that it's the edgeboard connectors, because that will be the easiest thing to fix. Tom is right about DeOxit D5. Caig does make a spray just for gold contacts, but D5 is a more general purpose cleaner and will be more useful.

But use any gentle contact cleaner. Pull the power plug. Remove the PC cards from the motherboard one at a time, clean the connector where it plugs in to the motherboard, and plug it back in. Do all the baords that way.

And look for a relay like Tom said. I'm thinking in a Delta it will be pretty small.

If it gets much beyond that, you'll probably have to get extender boards to get the PC boards up out of the machine so you can do some signal tracing with a scope. That may be more than you want to tackle.

Good luck
 
greg.hahn said:
Tom Wells said:
I have had the very same issue with several types of recorders. Usually it is a relay with poor continuity at the contact faces.
Is this on both channels? If so, the noise may be power supply related, but since it's only in recording, probably not.
The low levels could also be due to oxidized relay contacts. There is a product made by Caig Laboratories called De-Oxit D5.
If you can get a can, you can literally spray away most crackles, clicks, pot noises, "funny" switches, etc.
I consider it magic. It is not a cleaner, but rather, chemically removes oxides and sulfides on the contact surfaces.

Look for a relay that pulls in during record. Often they are soldered in, but have a removable rectangular plastic cap.
Click to expand...

You should pray that it's the edgeboard connectors, because that will be the easiest thing to fix. Tom is right about DeOxit D5. Caig does make a spray just for gold contacts, but D5 is a more general purpose cleaner and will be more useful.

But use any gentle contact cleaner. Pull the power plug. Remove the PC cards from the motherboard one at a time, clean the connector where it plugs in to the motherboard, and plug it back in. Do all the baords that way.

And look for a relay like Tom said. I'm thinking in a Delta it will be pretty small.

If it gets much beyond that, you'll probably have to get extender boards to get the PC boards up out of the machine so you can do some signal tracing with a scope. That may be more than you want to tackle.

Good luck
Click to expand...

Just a complementary note perhaps useful: each time I start a deck (Any of the free) I always get a short "click" sometimes louder than others but overall low. Hints? By the way, thank you both!
 
SFM-Ptgal said:
Just a complementary note perhaps useful: each time I start a deck (Any of the free) I always get a short "click" sometimes louder than others but overall low. Hints? By the way, thank you both!
Click to expand...

I would guess that to be power supply related. This is a time when an oscilloscope is invaluable. I'm going to bet that if you watch your power supply voltages, you can see them jump when you press start.

There you're looking for a big capacitor or a voltage regulator.
 
I don't remember on the Deltas, but many cart players have a holdoff circuit in the audio which keeps it muted for maybe 50 milliseconds at startup, so you won't heard the thump fromt he solenoid, or the ramp up of the sound if the tape is close cued. I'd change all the electroliytic caps - including tantalums - in the machine. Given the age of Deltas, I'd do that anyway.
 
littlejohn said:
I don't remember on the Deltas, but many cart players have a holdoff circuit in the audio which keeps it muted for maybe 50 milliseconds at startup, so you won't heard the thump fromt he solenoid, or the ramp up of the sound if the tape is close cued. I'd change all the electroliytic caps - including tantalums - in the machine. Given the age of Deltas, I'd do that anyway.
Click to expand...

Wow, I forgot about that circuit. In the old ITC "Premimum Line" SP/RP/3D that used to crop up sometimes. One or more of the capacitors associated with that circuit would dry out and it would make a pop when you started a cart.

You're probably right, they probably did the same thing in the Deltas. The Deltas just weren't around long enough for all those things to go wrong with them. (And I think they had better capacitors.)
 
All electrolytics go funny sooner or later.
They're like.... No. 1 in order of likely electronic component failure.
Or so.
 
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