TRS-80 Model 4 and Model III Tape Operations

[docangle]

I have been trying to read from a Tape Drive, and can't get it to work. I have tried two different cables, multiple tape recorders, and tapes. I can use the CSAVE "TEST" Command to save the file under basic, when I remove the wires and playback through the tape speaker I hear the appropriate sound, but when I use the CLOAD "TEST" command the tape blows through this section, I get no indication on the display. I have tried every single volume level, but nothing seems to work. I did test both cables on the Model III in multiple video game to make sure I hear audio sounds and it works fine.

 

[LambdaMikel]

Are you running Disk BASIC? In that case, you might have to use CMD "T" to disable interrupts before cassette operations (and re-enable via CMD "R")?

Nice write-up: http://48k.ca/cmdt.html

 

[ldkraemer]

Try Cassette Basic by Holding the BREAK Key DOWN, and KEEP it Down, then turn on Power and
when you see characters on the screen, RELEASE the Break Key. Tap Enter twice and you are
in Cassette Basic.

I've attached the Page of the Manual with the Recorder's connections.


Larry

 

[docangle]

I should have been clear I am trying this from Cassette Basic, not Disk Basic. I have read the directions and they seem to be correct. I don’t have the original Tape Drive but I have a Radio Shack Tape recorder that does have Ear, AUX, MIC, and Remote plugs. I also have a General Electric Computer Tape Recorder that I use on the TI-99/4A. It doesn’t have an Aux port but has the other ports. Both Tape Recorders work fine on the TI-99/4A

 

[TRS-80.com]

You might want to try plugging the EAR from the TRS-80 into the LINE IN of a PC and using AUDACITY or something like to that to record it. You can then test the output in an emulator to ensure that the TRS-80 is sending the correct data. You can also try to reverse it and CLOAD from AUDACITY. This will allow you to rule out a cassette recorder issue ... such as a slipping/slow motor.

 

[rlauzon]

Didn't the Model III have a slow and fast tape mode?

You'd have to select the correct mode to go with the tape you are using.

 

[docangle]

Didn't the Model III have a slow and fast tape mode?

You'd have to select the correct mode to go with the tape you are using.

I tried slow mode on both machines, did not work

 

[ldkraemer]

For SLOW (500) or FAST (1500) Rate, when you see CASS? Type in either L or H on the Keyboard
for LOW or HIGH Speed. LOW is compatible with TRS-80 Model 1, and High is for Model 3 & 4.

The Mini Plug that goes into the Earphone Jack is the INPUT to the Model 3 or 4.

Larry

 

[Petrofsky]

I did test both cables on the Model III in multiple video game to make sure I hear audio sounds and it works fine.

But of course that only tests the output lines of the cables, and your problem is in the input. I would use an ohmmeter to check the connections from the input phone plug to the DIN connector.

But considering that you've tried two different cables, it does sound like the problem may be inside the Model III, which will be harder to diagnose and fix. You can find the schematics and theory in the technical reference manual.

The 1500-baud and 500-baud load routines rely on different components on the motherboard, so it's possible 500-baud is broken but 1500-baud isn't, so try both. Also, 1500-baud is less volume-sensitive and generally more reliable, so I'd try to get that speed working first. (The 500-baud and 1500-baud output, and sound effects, are all using the same output components, which are separate from and simpler than the input circuit, so the fact output seems to be working doesn't really tell you anything about whether your input is working.)

And as trs-80.com said above, you may have better luck testing the TRS-80's input by using clean audio output from a modern computer, using something like the Playcas utility. That would eliminate the possibilities that the problem is that the tape recorder's fidelity isn't quite good enough, or that the recording is bad because the TRS-80's output was slightly garbled.

 

[docangle]

Okay, I feel dumb!!!! I used a meter to tone out the wires, and the stupid cables I ordered from Amazon are wired reverse! Red is Yellow and Yellow is Red!!!!! Switched the wires around and I can save and load programs! I swore I had tried this earlier, but may be on a different cassette recorder, and I might have two separate issues. I am going to pull out the GE Recorder and try it with that device.

 

[docangle]

But of course that only tests the output lines of the cables, and your problem is in the input. I would use an ohmmeter to check the connections from the input phone plug to the DIN connector.

But considering that you've tried two different cables, it does sound like the problem may be inside the Model III, which will be harder to diagnose and fix. You can find the schematics and theory in the technical reference manual.

The 1500-baud and 500-baud load routines rely on different components on the motherboard, so it's possible 500-baud is broken but 1500-baud isn't, so try both. Also, 1500-baud is less volume-sensitive and generally more reliable, so I'd try to get that speed working first. (The 500-baud and 1500-baud output, and sound effects, are all using the same output components, which are separate from and simpler than the input circuit, so the fact output seems to be working doesn't really tell you anything about whether your input is working.)

And as trs-80.com said above, you may have better luck testing the TRS-80's input by using clean audio output from a modern computer, using something like the Playcas utility. That would eliminate the possibilities that the problem is that the tape recorder's fidelity isn't quite good enough, or that the recording is bad because the TRS-80's output was slightly garbled.

I did try using the PlaCAS utility on a modern PC, after knowing which wire to connect. I am getting ** when loading a Basic program, but when PlayCAS is finished the computer is still waiting for more data. I have tried multiple volume levels and LNW 1Khz. I am not getting any "D" just "*". Forgot to add that I only get "*" when LNW 1KHz is selected.