Latest kernel gives blank screen when it boots

[Frank McCormick <mccfrank@gmail.com>]

I have spent the last several days setting up Fedora on
another partition. When it came to boot back into Debian Sid
this morning I discovered my screen goes blank after the first
few seconds.
The previous kernel is fine. 4.18.0-2-amd64 #1 SMP Debian 4.18.10-2 
(2018-11-02) x86_64 GNU/Linux

This is the output of inxi-


System:    Host: franklin Kernel: 4.18.0-2-amd64 x86_64 bits: 64 
compiler: gcc v: 7.3.0 Desktop: IceWM 1.4.2 info: wbar
           dm: LightDM 1.26.0 Distro: Debian GNU/Linux buster/sid
Machine:   Type: Desktop System: LENOVO product: 5536E2F v: ThinkCentre 
M90p serial: <root required>
           Mobo: LENOVO model: N/A serial: <root required> BIOS: LENOVO 
v: 5JKT47AUS date: 07/13/2010
Battery:   Device-1: hidpp_battery_0 model: Logitech Wireless Keyboard 
K330 serial: 4016-b1-f3-8c-d1
           charge: 100% (should be ignored) rechargeable: yes status: 
Discharging
           Device-2: hidpp_battery_1 model: Logitech Wireless Mouse 
M215 2nd Gen serial: 401b-11-8a-8b-04
           charge: 100% (should be ignored) rechargeable: yes status: 
Discharging
Memory:    RAM: total: 3.54 GiB used: 486.8 MiB (13.4%)

PCI Slots: Permissions: Unable to run dmidecode. Are you root?
CPU:       Topology: Dual Core model: Intel Core i5 660 bits: 64 type: 
MT MCP arch: Nehalem family: 6 model-id: 25 (37)
           stepping: 2 microcode: 11 L2 cache: 4096 KiB bogomips: 26601
           Speed: 1463 MHz min/max: 1197/3326 MHz boost: enabled Core 
speeds (MHz): 1: 1464 2: 1463 3: 1463 4: 1463
           Flags: acpi aes aperfmperf apic arat arch_perfmon bts 
clflush cmov constant_tsc cpuid cx16 cx8 de ds_cpl dtes64
           dtherm dts ept est flexpriority flush_l1d fpu fxsr ht ibpb 
ibrs ida lahf_lm lm mca mce mmx monitor msr mtrr
           nonstop_tsc nopl nx pae pat pbe pclmulqdq pdcm pebs pge pni 
popcnt pse pse36 pti rdtscp rep_good sep smx ss ssbd
           sse sse2 sse4_1 sse4_2 ssse3 stibp syscall tm tm2 tpr_shadow 
tsc vme vmx vnmi vpid xtopology xtpr
           Vulnerabilities: Type: l1tf mitigation: PTE Inversion; VMX: 
conditional cache flushes, SMT vulnerable
           Type: meltdown mitigation: PTI
           Type: spec_store_bypass mitigation: Speculative Store Bypass 
disabled via prctl and seccomp
           Type: spectre_v1 mitigation: __user pointer sanitization
           Type: spectre_v2 mitigation: Full generic retpoline, IBPB, 
IBRS_FW
Graphics:  Device-1: Intel Core Processor Integrated Graphics vendor: 
Lenovo driver: i915 v: kernel bus ID: 00:02.0
           chip ID: 8086:0042
           Display: x11 server: X.Org 1.20.3 driver: intel resolution: 
1920x1080~60Hz
           OpenGL: renderer: Mesa DRI Intel Ironlake Desktop v: 2.1 
Mesa 18.2.6 direct render: Yes
Audio:     Device-1: Intel 5 Series/3400 Series High Definition Audio 
vendor: Lenovo driver: snd_hda_intel v: kernel
           bus ID: 00:1b.0 chip ID: 8086:3b56
           Sound Server: ALSA v: k4.18.0-2-amd64
Network:   Device-1: Intel 82578DM Gigabit Network vendor: Lenovo


Can anyone help? Where should I look first.

Thanks