From 493330ae01f47c4bc613508cb5f8d0232537947a Mon Sep 17 00:00:00 2001 From: Thomas Quinot Date: Sun, 6 Jul 2025 17:13:24 +0200 Subject: [PATCH] Minor presentation fixes --- _source/_posts/2025-05-18-ti99-4a-restoration-ep6.md | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/_source/_posts/2025-05-18-ti99-4a-restoration-ep6.md b/_source/_posts/2025-05-18-ti99-4a-restoration-ep6.md index d1cb6cc..57ceaa2 100644 --- a/_source/_posts/2025-05-18-ti99-4a-restoration-ep6.md +++ b/_source/_posts/2025-05-18-ti99-4a-restoration-ep6.md @@ -8,22 +8,25 @@ categories: ## Where we are: funny L600 -I captured more traces showing voltage before L600 (i.e. at the net labeled "8" from the power supply in Sams Computer Facts) and after it (i.e. at the CPU's Vcc pin), also recording the min and max voltage. +I captured more traces showing voltage before L600 (i.e. at the net labeled "8" from the power supply in Sams Computer Facts) (yellow) and after it (i.e. at the CPU's Vcc pin) (purple), also recording the min and max voltage. -{% figure caption:"Old CPU" %} +{% figure caption:"Old CPU, L600 not shunted (bad)" %} ![Old CPU, L600 not shunted (bad)](assets/TI-resto/20250703-oldCPU-L600.png) +{% endfigure %} + +{% figure caption:"Old CPU, L600 shunted (OK)" %} ![Old CPU, L600 shunted (OK)](assets/TI-resto/20250703-oldCPU-shuntL600.png) {% endfigure %} We are seeing: * very large voltage variations downstream of L600 when it's not shunted -* interstingly, slightly different readings on the two probes even when shunted with a wire :frown: +* interstingly, slightly different readings on the two probes even when shunted with a wire 🤔 ## Replacing the CPU & a provisional conclusion The hypothesis at this stage is a marginal CPU that draws a little too much current, so I'm trying to replace it with another one from eBay. -{% figure caption:"New CPU" %} +{% figure caption:"New CPU -- it works!" %} ![New CPU, L600 not shunted (OK)](assets/TI-resto/20250703-newCPU.png) {% endfigure %}