Message Board

Pinouts of the tl074/84 would not match.Pins 1+ 2 and 13 +14 are shorted on the pcb layout.It would not work as 1+2 and 13+14 are the +/- inputs for amp 1 and amp 4.Can't work as a buffer with the inputs shorted together.
It has 2 2520s.Tha A1 has only one..Thanks for the input.

That is the schematic,but the nomenclature,(R1,R2 etc), don't match the schematic.For example, R111 on my PCB is R78 on the schematic.I found a description of the three types made.Mine has the Datatronix labeled PCB.It describes a daughter pcb assy. for that version.Pins 1+2 are shorted, as is 6+7,8...

I don't have a way to upload the schematic,but a search on 'API 550a 'schematic will show you.There were some resistors scortched when the 2520 failed.They are not numbered the same as the schematic that's on the web.

Hello all.I have aquired a disassmbled API 550a in need of service.I have built the GAr 2520 to replace the one that was fried,but there is something missing in the middle of the board.Someone soldered a 14 pin socket in the 'J1' position.The schematic shows some amps labeled 'A1',A2 etc,and a small...

Pinch roller and belts and lots of other parts for Tascam and Teac tape decks can be gotten from...wait for it.........wait for it.......The Parts Dept at Teac/Tascam,(if you are in the U.S.) 323-726-0303 ex 840 or Parts @ Teac.com-Cheaper than EB@y

Or it's the Capstan belt...

Lots of pro tape machines used freq.control of the capstan moter.It was used when the tape machine was locked to SMPTE and needed varispeed to stay locked to the Smpte source,(square wave),usually another tape deck or video deck.The enable pin says low.That means"active low" which means the function...

It sounds like you have a component,(Transistor ,Diode,I.C.cap. etc.) that is failing/drifting when hot on the "reel servo Pcb"It's the same one you are tweaking R112/212 on.With the component failing your back/takeup tensions are drifting.You could get a can of freeze spray and cool components afte...

Do a search.There was also a few posts about modding the 1588 for lower noise and better bass response.

Verify there is bias at the head with either an O-scope or a meter that will respond to the bias freq.I use a analog VTVM. Contact the Parts Dept at Teac,(Parts @ Teac.com),for the parts you need,or take to a tech that has the proper equipment to diagnose and repair.

The meter has to respond to the bias freq. which usally is 100-150KHZ.I don't think the mdl.87 will respond.Most of the "cheaper" DMMs only have a freq. response up to 100HZ.They assume you will use it to measure 120VAC 60 hz.An analog VTVM will get you what you need, and can be much more useful dow...

Remember,you are reading the voltage unloaded.Adapters most of the time read higher when measured unloaded

open p.r.solenoid,or a control/driver problem not energizing the soleniod.

If the "tape in" sensor was flaky,the machine would "think" you are removing and inserting a different tape,and that would reset the counter...

What you didn't mention is if the input, meter, playback levels, and EQ are set correctly.Without all the above set up correctly, the bias adjustments are invalid. The +3 mentioned in the manual are not for setting up input levels.The operating level of the MS 16 is 250nm reference fluxivity,+3 Db a...