Another PAL-1 is born

[Allen Evenson]

Built base kit over two sessions yesterday and today. No problems using Interactive BOM, a very nice feature - though I did modify build order slightly.

Did a smoke test before inserting chips. 

Computer fired right up and I quickly entered the counting program from the PAL-1 user manual. At first, there was no joy, but I noticed that the SST switch was in On position (interesting that I didn't set vector yet). Flipped switch, and off she went. Decided to cut my session short as my supply is a 9V. I need to get a 7.5V (have a 300ma 7.5V but it didn't power board, not sure if supply is bad or not enough power for board)

Next step is to get a null modem adapter to try serial. I have a USB serial cable. Need a terminal program for Win10 also.

After that, I'll start building the expansions and playing around with it. 

Attached photo of PAL-1 moments after first power up.

Cheers,

Allen

[GN L]

Thanks for your sharing!
&
Happy hacking 6502 ;)

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Best,
Liu

[Allen Evenson]

One of the expansions I'm looking forward to is the extra ROM module. I noticed though the paperwork in the kit did not mention Fig Forth bit the website does. I'm hoping it is there as that is one of the things I want to try with the PAL-1.

Cheers,

Allen

[Hans Van Slooten]

Nice job!

Just a heads up: you need to use s straight-through serial cable. Null modem will swap TX and RX which isn’t what you want for the PAL-1.

Hans

[GN L]

The PAL-1 ROM has Fig Forth imported by Jim. You can find the details at http://pal.aibs.ws/assets/Operation_guide_PAL-1_EPROM_Expansion_Card.pdf

Best,
Liu

[Allen Evenson]

Ok. I was under the assumption I needed the null adaptor. I use need a gender changer then and have one. Now to look at terminal options for Win10.  Suggestions?

[Hans Van Slooten]

Teraterm works well and allows you to see the delays for keypresses and newlines which helps to prevent garbling pastes. 

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[Hans Van Slooten]

“Allows you to set”

[GN L]

I use Tera Term (https://ttssh2.osdn.jp/index.html.en) on Windows.

You can try a “normal” USB to RS232 cable with gender changer to connect to the PAL-1.

Best,
Liu

[Allen Evenson]

Thanks for tips on TeraTerm. I have it downloaded now.

 Regarding Voltage on PAL-1: Is 9V safe to use long term?  I seem to remember 12V needed if using cassette Interface?

 I may sneak down to test serial later this evening.

Cheers,

Allen

[Allen Evenson]

Serial is working!

[GN L]

9V is OK, but you will need a heatsink with L7805. The 12V in cassette interface is boosted from 5V.

Best,
Liu

[Greg Holdren]

There are several 5V DC to DC switching regulators that will drop into the TO-220 style foot print 7805 regulator. Way more efficient with very little to no heat over a wide range of input voltage.

Greg

[Allen Evenson]

Well... something bad sems to have happened. Machine was working fine - I purchased a nice 7.5V 1A adapter and things were going well. Worked through intro section of First book of KIM (a few hrs on the PAL with no prolems the other day and was going to enter Addition program tonight. Suddenly, after a few minutes display went dead. On reset only left-most LED lights (all segments). Have tried several times resetting with same results - no display or leftmost LED only. Also tried serial with no luck.

What do I need to do to start trouble-shpooting?

Frustrated,

Allen Evenson 

To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/154a1117-8adf-4abe-961a-9329691a8d32n%40googlegroups.com.

[GN L]

Hi Allen,

If all the operation environments is unchanged, the most likely problem is the 6532 failed. I had another similar problem before. You can try to change the 6532 on the RIOT expansion to confirm.

If the problem is with the 6532, I’ll send you a replacement chip to fix the problem as the purchase is within 90 days.

Thanks,
Liu

[Allen Evenson]

Hi Liu,

Thanks for the quick response. I swapped the 6532 with the one from my unbuilt 2nd RIOT expansion. Same results - the power and left-most display LED light only - same results with either chip. I put the original back in and tried again with the same results.

What is my next step?

Regards,

Allen

[GN L]

Then I think the problem is not with the 6532, the next thing to check is the 6502, 74LS145 (U1), 27C64.

You can try pushing all the ICs into the socket a little harder to confirm that all the pins are firmly contact with the socket. Then you can try to replace the 6502 (I don’t know if there is a 6502 around you) to see if the 6502 is the problem.

74LS145 and 27C64 are a bit difficult to check without tools, but these two chips are hardly fail, I think you can check the 6502 first.

Best,
Liu

[Allen Evenson]

I tried pushing in the chips to make sure all were seated correctly. 

No change. 

I don't have access to another 6502 to test.

Very strange that all was fine for several hours before problem showed 

[GN L]

It is strange…

Since the 74LS145 is brand new and the 27C64 is NOS, and these two have no errors reported before. I'm tend to the problem caused by the 6502.

You can do a NOP test on the 6502 processor like https://www.dmcmillan.co.uk/blog/testing-a-6502-cpu-on-a-breadboard or http://www.6502.org/mini-projects/nop-gen/nop-gen.htm

If you have some logical tester and eprom burner, like TL-866II, you can check all the logical chip and the 27C64 with it.

Best,
Liu

[Allen Evenson]

Ordered a 6502 from Ebay - I may try the NOP test on the breadboard in the meantime.

Regards,

Allen

[GN L]

Looking forward to your test result.

Best,
Liu