More tape machine woes: crosstalk in sync only

[Brian Roth]

Congrats!! Just a suggestion re. the logic chips: I would use high quality sockets for them. Machined pin types from a decent, trustworthy supplier.

Bri

 

[EmilFrid]

Thanks for the advice. I was going to socket then and will look for good quality ones. I hade a few with machined pins but only for dip-8. Same supplier probably has for dip-14

 

[RoadrunnerOZ]

Good news!

As I went through the machine I reflowed a few more joints on the connector board, and now the crosstalk in sync is at a normal level, ie not excessive anymore. Thank you so much for all the guidance. Now the only thing left is to replace a few logic IC's on some of the amp boards as they went bad at the same time this happened. But that is not a big deal, only four IC's on a few boards.

This forum rocks

Good news indeed. Well done.
Over the years as machines get older and older the integrity of the solder joints will become compromised and where there is constant flow of DC or audio the joints will erode over time.
I usually reflow all joints on a board if I’m getting intermittent and weird faults.
Cheers on the return to sanity.

 

[EmilFrid]

Thanks very much, and thank you for the support throughout the thread. Yes, I guess reflowing joints should be something I do more often on my old machines.

Now patiently awaiting the next catastrophe

 

[Johnny1234]

Happy your machine is working again. An old boss of mine said hit it and see if it works, once is maintenance but twice is abuse.

 

[EmilFrid]

Lol that is always the first thing you do

 

[Brian Roth]

Happy your machine is working again. An old boss of mine said hit it and see if it works, once is maintenance but twice is abuse.

I remember many years ago a visit to a struggling UHF TV station. They had several old RCA 2" "Quad" video tape machines. RCA stickers were randomly on the metal cabinet. My friend/tour guide explained those were the locations to try pounding on the cabinet to correct a fault.

Bri

 

[RoadrunnerOZ]

I remember the old MCI JH24 - every morning before starting recording or mixing for the day you’d give the record/repro card drawers a good bash so everything would work. Once a week or if the bash didn’t work you’d pull and reseat all the cards. Worked fine that way for years as no one wanted to fit new connector bases - no internet to source bits easily and a long downtime for a busy studio to allow to do the job.

 

[Johnny1234]

I remember the old MCI JH24 - every morning before starting recording or mixing for the day you’d give the record/repro card drawers a good bash so everything would work. Once a week or if the bash didn’t work you’d pull and reseat all the cards. Worked fine that way for years as no one wanted to fit new connector bases - no internet to source bits easily and a long downtime for a busy studio to allow to do the job.

Sounds like you worked at Media Sound in NYC. LOL

 

[RoadrunnerOZ]

Sounds like you worked at Media Sound in NYC. LOL

No. Was one studio in Melbourne in the ‘70s and two in the ‘80s one in Melbourne and one in Sydney and later two in Byron Bay in the ‘90s - studio 2 at one studio and main studio at the other. Coincidentally the same tape machine and MCI console from the first studio migrated to another studio that I worked in and then yet another in the ‘90s - same tape machine, same kickstart quirks Some comedian had taped a rubber mallet to the side of the machine when it was shipped.

 

[Walrus]

Ah yes, I remember well the MCI 24. You'd carefully adjust the audio cards as you did a line up, then shut the draw and
watch as 3 or 4 meters would suddenly change by a dB or so!

 

[RoadrunnerOZ]

Yeah they didn’t always make proper contact with the edge connector. One of the machines I dealt with ended up getting new connectors fitted and seemed ok after that

 

[EmilFrid]

I'm curious. The little crosstalk that is left gets even smaller when I put the hum shield on. What's the science behind this? Does the mu-metal absorb some of that magnetic energy?

 

[RoadrunnerOZ]

Must do I would guess. The tape itself would also add a little damping.