Monacor Echopac ME350

[dirtyhanfri]

Hi

I'm troubleshooting a Monacor Echopac ME350 tape delay unit. The problem was described as no signal in the echo path. I have no experience with tape devices. The unit uses a small tape, similar to the classic cassette tape in different format, but tape width and head looks the same as those used in old cassette players.

There are two heads, eraser / writer (it has two wires coming from PCB), and the read one (one wire going to the PCB). I have no signal in the wire going to the heads. I tried unsoldering what looks to be the signal wire in the erase / write head and it has a copy of the input signal on it but it gets lost when I solder it to the head. On the other hand, I tried also to unsolder the wire going to the reading head and inject signal on it, then I have "wet" signal in the unit output.

I guess it's time to replace the tape heads, right? The thing is I have no idea about models and references when it comes to tape heads, but in eBay I find a lot of similar items, it's just some kind of 'standard' and I can get any pair? or is something critical I should check before ordering?

Thanks in advance.

Attached is the picture of the heads, the upper one looks to be the recording one (note there's one missing wire, I unsoldered it to trace signal).

 

[rock soderstrom]

Hi, a basic info for your device or similar models. I am not sure if this applies here but my experience with such cartridge based devices is the following.

If the effect signal is very weak or not present at all, it can often be due to the cartridge. The tape is pressed against the tape head by a foam. Over time, the foam dissolves and as a result, the distance between the tape and the head is too large, making the signal very weak.

I could already observe this problem several times. The solution would be a new cartridge or replacement of the foam. This is also described somewhere on the Internet.

 

[dirtyhanfri]

Thanks for the tip. I had no idea about that, I'll check tomorrow as I'm out of the shop now.

I was unsure about the head being bad as there are passive devices and didn't look to prone to fail. (From my understanding, aren't they essentially half a transformer with the induced magnetism received by the tape instead the secondary coil?)

So I guess it's normal not getting signal when probing in the coil?

Thanks

 

[rock soderstrom]

I am no expert on tape heads but they must show electronic continuity. I believe they are basicly the equivalent of a guitar pickup.

Here you can find info regarding the cartridges and the foam pad problem.

http://estecho.com/2017/01/tape-delay-cartridge-reference/

 

[dirtyhanfri]

Thanks for the link, actually my tape is one of those Apollon shown in the article.

I found a seller in etsy which sells foam kits for this tape at a reasonable cost (4,5€ for 10 units), sadly it doesn't send to Spain, so time to look for a suitable foam.

 

[mjrippe]

Degauss (de-mag) the heads as well as the rest of the metal parts of the tape path while you are in there. This can improve levels and HF response in particular. And of course clean it all with 99% isopropyl.